Chess practice at all speeds is good for learning chess. I have played them all from 15 seconds to correspondence. I even played with 1 minute against 10 with the rule that the time is not reset after each game, instead the following games continued with elapsed time. I won seven games in the same minute. I cannot do that now, but I still recognize the benefits of practicing at various time limits. There were no video tapes then outside of television studios and of course nothing more modern than that to back up that story, just old-fashioned witnesses (if their time hasn't elapsed). One thing to know is yourself. If you play blitz before tournament games, it may affect your time management favorably. You have to learn from experience how mixing time limits affects you. If you play 1 minute chess and then 5 minute chess, you should play at the longer limit better. If you play 5 minute chess and then 1 minute chess, the reverse may be true, at least at first. Blitz sessions can give you a better grasp of your repertoire and your opponent's than one long game. However, the only true way to play chess at any speed is with the touch move rule. Moves back or touch clock should not apply. Chess playing and learning is enhanced with responsibility. Do not play out certain dead draws, such as rook against rook in blitz. If you are not playing for money, there is no reason to do so. If you are playing for money, it is better to play more games per hour and not waste time.
Is Quick Chess Bad for You ?

Many "slow chess" tourneys end up using fast and blitz chess for tiebreakers. The masters need to know how to play at all speeds.
My live chess stinks because I rely heavily on opening databases for correspondence chess (not to mention extensive analysis board work), and I don't have either crutch in live chess. Because of this I have started playing more live chess, because I want to -learn- openings and not just be able to look them up. ;)

I find that I tend to make mistakes in blitz that I would never make (or at least hope I wouldn't) in a long game; however, blitz games have given me insight on how to solve large problems in a timely fashion. I tend to have the clock on my side whenever I play chess as a result.

When I was a youngun there were two types of "real chess," OTB and Correspondence. We played lots of blitz while the veterans tsk tsked from afar. Now they settle important tournaments with blitz.
I still don't think it's real and for almost all of us we risk having a superficiality induced into our slower games. As GreenLaser noted, blitz is not a bad tool to practice opening repertoire.
Maybe for titled players blitz can be real chess but for the rest of us it mostly just entertainment, at best.

I disagree that the quick and blitz games is better for your development that the long game (slow). The simple fact is that in quick you are basically giving up positions and making terrible mistakes in hopes that an all out assault will crush the player, or just make random moves in anticipation that the player will crap out. When you are playing long, you are thinking about positions strategically. It becomes a battle of the brains in long and correspondence chess.

I don't think blitz is a great learning tool. I find it difficult to analyze the necessary positions and end up making a lot of stupid moves just so I don't time out. Also, the disconnect issue makes it frustrating!

i agree it causes,u too stop planning and leads to quick and a general defeat but v should use it on sudden deaths

I think to be good at quick chess you would have to have played A LOT of chess. Because in most cases you have seen the position before and know what to do. If you havnt you will just be making randomish moves with only 2-3 move calculations.

Chess played at all speeds is good for your development. Playing at only one time limit is limiting. Below is an example of blitz at 8 to 1 odds.
http://www.chess.com/article/view/mating-the-tuna-in-deep-water-at-the-flea-house-of-the-august-moon

It is possible maybe for blitz to help. I think to help you find the best move as quickly as possible. I do not play it, I would rather play chess slower. I do not make as many careless mistakes.
Generally quick chess is not good for most situations. I would say there is an exception to this an that exception is that you will experience continuity. Many times with turn based chess and especially with playing many games at the same time, unless you review the previous moves before your next move you lose continuity and your possible thought process of the plan of attack. Also you lose an idea of what your opponent's possible line of attack might be and how to counter that plan.

Blitz is good for practicing your openings. I've neglected blitz too much recently. Of course, be wary of blitz-specific tactics such as pre-moves, wood-pushing, unsounds sacs and openings, etc. as these things can diminish your play in OTB games.
slimcheffy> My thought is that it is actually bad for you, forces you to move quickly and carelessly, is it even considered "real" Chess ??
Nobody forces you to do anything. I try not to play carelessly at any time control.

thanks escral, I have actually quit playing live chess altogether...I can't seem to win a fast game no matter what I do....I don't understand it....
We have similar experiences, slimcheffy.
"Quick" chess has pluses and minuses. But no matter what, I like playing chess in normal time.

Quick chess may offer certain benefits (time management, and quick decision making abilities, but it generally is too fast for you to develop fundamental chess-where you strive for the best move always. I hardly play "blitz" anymore...I realised that the focus is more on outlasting your opponent until the flag falls...even if you just "push wood"...
Time is the 4th dimension! Good training to think fast! I'm not so crazy about Quick, but Blitz is good for you.