I would be more willing to employ a gambit line (that I knew well of course). Most known gambit lines tend to make the gambiteer have a disadvantage in (G/120 30 increment with 1 hour after 40 moves) the opponent just has way too much time to find ways to keep his material safely this is even more evident the higher the level you play in. But in a G/30 I would not mind playing something dubious even (albeit knowing FULL WELL what the consequences are and how to play the position) because it is MUCH less likely for the opponent to find the refutation, even if they do find it and spend 20 minutes on the clock you alreayd have your work cut out for you and can probably still push for a win. Also Trap lines can be employed in a G/30 with much less risk than a G/90 or classical. Apart from lower opening risks I would say the rest is about the same.
Shorter time controls : Should anything change about one's chess preparation?

I would guess opening and endgame knowledge counts more as time is more precious. You can sort of find your way around in these if you spend a lot of time, but being able to assess certain endings as W/L/D quickly (and even drilling some of them) or blitzing the opening while your opponent eats up time should be very advantageous.

From what GM Jessie Crii said is that the initiative, keeping the pressure and threats going is the key in fast time controls <=g30. Making your opponent spend more time on the clock looking for the best defense.

Most weekend 1 day tourneys are G/30 +5 ? Does that even count towards your standard rating? Those are all blitz tournaments right? I went to a G/60 +5 and it counted toward my standard rating... and I thought that time control was really too fast to count.
If you enjoy positions where you're attacking and have to find moves that keep the initiative, then sure, learn some trappy gambit stuff -- otherwise I'd just stick to what you're most comfortable with. I wouldn't change any preparation unless you're uncomfortable with blitz to being with. As long as you're able to make a quick assessment, and then trust it without spending time going over it again, checking for errors or looking for finesse moves over and over etc. then you should be fine.
Endgame drills don't sound too bad. Maybe give yourself 3 minutes and a drawn position vs the computer to make sure it's easy for you, or a winning position and win it. You could play some 30/0 online (or at a club) to see if you have any issues with being too fast or slow, and how comfortable in general you are with it.

Most weekend 1 day tourneys are G/30 +5 ? Does that even count towards your standard rating? Those are all blitz tournaments right? I went to a G/60 +5 and it counted toward my standard rating... and I thought that time control was really too fast to count.
USCF actually states that unless it is G/29 or below, it is still considered standard time control, though TDs submit it as dual. Yeah ... the times are a-changing :)

I don't understand how anyone can think 15 minutes is even too quick. I know 5 min is pretty quick, and makes you do a lot of mistakes, but for most games, having 3-5 minutes in a difficult position is enough to win the game...
I know the style of playing maybe a bit different in correspondence chess, where you may think of every single possible move/combo, but in the end you might arrive at the same decision as 2 minutes ago.
With 10 minutes, it seems that you can make most of the accurate moves. Some beginners find it too difficult, because they think hard on even simple opening moves. But 15 minutes seems adequate time to consider most checks/pins/forks and positions.
Am I mistaken?

I don't understand how anyone can think 15 minutes is even too quick. I know 5 min is pretty quick, and makes you do a lot of mistakes, but for most games, having 3-5 minutes in a difficult position is enough to win the game...
I know the style of playing maybe a bit different in correspondence chess, where you may think of every single possible move/combo, but in the end you might arrive at the same decision as 2 minutes ago.
With 10 minutes, it seems that you can make most of the accurate moves. Some beginners find it too difficult, because they think hard on even simple opening moves. But 15 minutes seems adequate time to consider most checks/pins/forks and positions.
Am I mistaken?
Have you followed the Amber tournament? The games there have a distinct difference from the usual 5hours games.
With that said, below a certain level I don't think beginners need hours for their moves.

I don't understand how anyone can think 15 minutes is even too quick. I know 5 min is pretty quick, and makes you do a lot of mistakes, but for most games, having 3-5 minutes in a difficult position is enough to win the game...
I know the style of playing maybe a bit different in correspondence chess, where you may think of every single possible move/combo, but in the end you might arrive at the same decision as 2 minutes ago.
With 10 minutes, it seems that you can make most of the accurate moves. Some beginners find it too difficult, because they think hard on even simple opening moves. But 15 minutes seems adequate time to consider most checks/pins/forks and positions.
Am I mistaken?
In short, yes .

Haha, well you got me :P.
I know masters use a lot of time, I just wonder what kind of crazy moves they been thinking of. Perhaps they need that much time in order to think through 6-9 moves ahead for at least 6-7 pathways?
As a computer chess engine may think via minimax trees.That would require hour+ games to think through clearly...

Haha, well you got me :P.
I know masters use a lot of time, I just wonder what kind of crazy moves they been thinking of. Perhaps they need that much time in order to think through 6-9 moves ahead for at least 6-7 pathways?
As a computer chess engine may think via minimax trees.That would require hour+ games to think through clearly...
Not only masters, I regularly use around 1 hour on a tactics problem. A great majority of them take at least more than 30 minutes, and I still blunder all the time. I sometimes can't believe I can actually play whole games in the same 30 minutes at all.
For some people, i.e talented people , the difference more time makes is less, but as tricklev has mentioned, the level of play varies even at the highest level as seen in Amber.

Good points from all of you.
Not to distract from the question, but it almost feels like the venerable old Master at the club who tells me that playing "sllllllllow" chess to get better may have grown in an era where classical time controls were prevalent, with more adults playing and less internet blitz-junkies. Likewise, I see high rated players in my area shun G/30 time controls like the plague. I've even heard one Expert say that he's afraid some kid who's never heard of a Philidor or a Lucena but happens to be a wizard at tactics might eat his lunch at that kind of a time-control and scalp him. :)

I feel like the Amber thing is more like, before in standard games, the GMs think positionally, but in rapid games, they play based on patterns and sometimes they don't put much thought into a positional move that ends up being an inaccuracy that will later prove costly (like a passed pawn or whatever).
Philidor, do you do tactics trainer, most of that requires 50-190 seconds. What kind of tactical problem would take an hour? Doesnt TT train you to do it in less time anyway?

Good points from all of you.
Not to distract from the question, but it almost feels like the venerable old Master at the club who tells me that playing "sllllllllow" chess to get better may have grown in an era where classical time controls were prevalent. Likewise, I see high rated players in my area shun G/30 time controls like the plague. I've even heard one Expert say that he's afraid some kid who's never heard of a Philidor or a Lucena but happens to be a wizard at tactics might eat his lunch at that kind of a time-control and scalp him. :)
That's an interesting subject in my opinion (whether playing only slow chess is better or not.) Anand had mentioned in an interview that Carlsen has grown as a chess player by playing thousands of blitz games online and that was an example of the role of technology and the new generation of players rising up to the scene according to him. Kramnik on the other hand claims not to play online (although he might just be hiding his alias), but he is still pretty good.

Philidor, do you do tactics trainer, most of that requires 50-190 seconds. What kind of tactical problem would take an hour? Doesnt TT train you to do it in less time anyway?
I did TT here for a while only to check it out, I did better than I expected. My main training is in chesstempo standard, where time isn't taken into account for rating points, it's just accuracy that counts, and I get difficult prolems (for my level at least) that requires time to check everything out. I also do a couple of blitz (like TT on here) everyday, and there's a huge difference in my ratings at both, similar to my blitz and online chess ratings here.

I don't change my repertoire, and don't think it's necessary, but that's just me. Of course with shorter time controls if you want you can more likely get away with super aggressive lines.
The only difference between my play on longer and shorter time controls is, you guessed it, time management. I often have to make faster decisions and less detailed plans with less time, but I realize that's part of the game.
I'm not sure if tactics are truly more important in rapid time controls, because there are also big changes in decision making, and what kind of plans you make as I mentioned, and of course you have less time to calculate out the tactics that do happen on the board. If you can only come up with cheap two move tactics your opponent could most likely still parry them.

Good points from all of you.
Not to distract from the question, but it almost feels like the venerable old Master at the club who tells me that playing "sllllllllow" chess to get better may have grown in an era where classical time controls were prevalent, with more adults playing and less internet blitz-junkies. Likewise, I see high rated players in my area shun G/30 time controls like the plague. I've even heard one Expert say that he's afraid some kid who's never heard of a Philidor or a Lucena but happens to be a wizard at tactics might eat his lunch at that kind of a time-control and scalp him. :)
Hmm, I tend to agree with the "venerable old master" at your club (play slllloowww) and I do think slow chess is what improves fast chess. Anand's account of Carlsen gaining strength through many online blitz games does not contradict this either as I'll try to show. Basically the reason is what masters and above like Carlsen are doing/gaining in blitz is not at all what class players are doing when they play blitz.
Heisman outlines 5 basic steps players use to chose a good move:
1. What are all the things my opponent's move does?
2. What are all the positive things I want to do?
3. What are all the candidate moves which might accomplish one or more of those goals?
4. Which of those initial candidates can I reject immediately because it's not safe?
5. Of the final candidate moves, which one is best I can find in a reasonable amount of time?
Step 5 being the most difficult, weighing the different future positions against each other, and this is the step strong players spend the most time on, while going through 1-4 "quickly and accurately." He says the further rated below 2000 a player is, the more difficulty they have in preforming 1-4 accurately or even consistently. For example you see the cheap shots very quickly, and also understand after each move what each position is trying to do.
So I think in general when Carlsen is playing blitz, he's trying out new openings or otherwise practicing mostly step 5, evaluating, and so he's learning new patterns and ideas such as in ____ opening the e3-d4 after black plays Be6 idea is (in)effectively met with _____.
When amateurs play blitz they're just reinforcing through practice the errors in their thought process by skipping or not completing 1-4, and (at least in my experience) not doing step 5 at all (at least until very recently maybe).
Compare it to practicing a piece of music, going over it at a fast tempo before you're able to hit all the notes correctly, it may be fun but you're practicing your mistakes. After you can play all the notes correctly at a slower or normal speed, then playing it quickly can be part of legitimate practice.
This is a brand new idea for me after having read Heisman (earlier today actually), but it seems to make good sense

Haha, well you got me :P.
I know masters use a lot of time, I just wonder what kind of crazy moves they been thinking of. Perhaps they need that much time in order to think through 6-9 moves ahead for at least 6-7 pathways?
As a computer chess engine may think via minimax trees.That would require hour+ games to think through clearly...
Masters don't use game trees at all (well, at least nothing like computers do). You may think they're spending all that time calculating deep and amazing moves, but really a master and an expert (200 points difference) may look at almost identical moves, and even lines, but what they're spending so much time on is the correct evaluation of the line after the moves. Ok yes they make sure to avoid any cheap tactics or pitfalls like that, but that is done relatively very very quickly, it's all about accurate evaluation. You or I can easily calculate/visualize 20 moves ahead, but the accuracy/strength of the moves would be dirt poor
This is how deep blue lost to Kasparov in their first match even though it calculated 1,000,000 positions per second, or how a master can give 1:10 time odds vs a beginner... because it's not all about calculation.

Haha, well you got me :P.
I know masters use a lot of time, I just wonder what kind of crazy moves they been thinking of. Perhaps they need that much time in order to think through 6-9 moves ahead for at least 6-7 pathways?
As a computer chess engine may think via minimax trees.That would require hour+ games to think through clearly...
Masters don't use game trees at all (well, at least nothing like computers do). You may think they're spending all that time calculating deep and amazing moves, but really a master and an expert (200 points difference) may look at almost identical moves, and even lines, but what they're spending so much time on is the correct evaluation of the line after the moves. Ok yes they make sure to avoid any cheap tactics or pitfalls like that, but that is done relatively very very quickly, it's all about accurate evaluation. You or I can easily calculate/visualize 20 moves ahead, but the accuracy/strength of the moves would be dirt poor
This is how deep blue lost to Kasparov in their first match even though it calculated 1,000,000 positions per second, or how a master can give 1:10 time odds vs a beginner... because it's not all about calculation.
I find this post a little confusing. What do you mean by evaluation? Like, your calculation ends up with your rook being on the 7th rank, or you losing your castling rights and you evaluate it as good or bad? If that's that case, I think it shouldn't take too much time, and after a certain amount of positional knowledge, isn't what exactly marks the stronger player from the strong. I think it's the actual calculation of lines that take up the overwhelming majority of time in a GMs analysis when say, he spends 10 minutes on a position, in post game interviews or conferences, GMs amaze me with the depth and width of their calculations. I also think an expert and a strong master look at completely different lines almost in all cases. I agree the expert may on rare occasions go even deeper than the master, but the strong master would blunder less in the calculation (which is not usually about evaluation) and look at more relevant lines. I also find it a little hard to believe you can calculate/visualize 20 moves with ease, I mean, wouldn't you struggle just a little bit?
Sorry if this sounds too negative, I didn't intend that. I probably understand something different from calculation and evaluation.
A time management question of sorts:
Most USCF weekend 1-day tournaments in my city (and I guess across the country) have a 30-minute (G/30, 5 seconds) time control. This can be considered depressing for those who like more time per move, but with less money going towards chess and more and more kids participating than adults, this is a sign of the times.
I needed to start getting more practice with this so I asked a stronger player if he had to adapt or change anything to the way he played (besides the obvious time-management + budgeting of time per move). Questions like =>
1. Did you switch to playing sharper opening systems that are more blitz-friendly?
2. Was being the better tactician of the two even more important with shorter time controls?
The overall answer received was that it shouldn't matter how fast the time controls are, a good player can play at any time control. The other tip I received was that if you knew your opening lines well, you should be able to blitz through the first 5-10 moves and thereby save more time for the rest of the game.
Was there any thing you had to change in your game between a fast (G/30) vs. a more civil time control (beyond budgeting your time differently!)?