What questions should I ask myself to determine my playing style.

Last two books I bought? Silman's complete endgame course and Yakov Neishtadt's Improve Your Chess Tactics.

When I came back to playing tournaments OTB after a 10 year break, my rating wasn't quite where it should have been (700 vs ~1500). In my first tourney back I went 5/5 in the U1400 section. Why? Every single opponent blundered a piece at some point in the game. None of them did it while we were still in theory. You could argue that I got some advantage out of the opening, and I did in a few games, but that wasn't why they missed the discovered check that netted me a piece. (for example)

If you're tactically aware, you won't give up material at any phase of the game.

Tactics save you from giving up pieces. Openings get you to a playable middlegame, or may give you a positional edge. Which would you rather have?

It doesn't change the idea that telling beginners to not worry about openings, and "just play good moves" is bad advice. 

The reason people say that is because so many people spend 80% of their time learning 12 moves in their favorite opening and then go on to drop a piece on move 18. They spend a disproportionate amount of time on the opening compared to how much it will help their game. Until you can either win in the opening (to the point that even if you give away a piece you're still winning), you need to be able to play the rest of the game well, or you'll still lose.

I couldn't have put that better. The return for investment on learning openings to the n'th degree doesn't make sense this early on in his chess career.

The last book I bought was "Learn from the Legends - Chess Champions at their Best"

Because I want to improve my endgame and this book was recommended to me.  First I'm going to review Dvoretsky though, so :p~~

I own a few opening books, mostly bought when I was new.  I haven't bought an opening book in the last... 5 years at least (and haven't read any of the ones I own).

I've very very rarely beat a new player because of some opening trap... they're usually not good enough to know openings anyway.  When pieces are blundered, 99.999999999999999999999999999% of the time (rough estimate lol) it's because of tactics not openings so I'm not sure what you're talking about.  I can only imagine this is especially true for scholastic players.

Honestly, -not- playing opening theory may help you instead of hurt you until at least class B, as you'll confuse your opponent and maybe make them push too hard thinking you're playing bad moves. If your tactics are good though, often they'll get themselves in trouble trying to punish you...unsuccessfully.

So nobody drops pieces after move 8 or so? That's the opposite of what I see at chess tournament.

Ok, let's spin the scenario:  Kid wants to learn chess. He joins his school chess club. The teacher shows him the opening principles, and they spend most of their time playing games and practicing tactics...even endgames. Opening theory is ignored, as we all know it should be until you are rated 2000 or whatever.

Kid goes to his first tourney. He hears other players saying things like "Sicilian" and "Queen's Gambit" and wonders what they are. He sits down as black and faces d4. He plays "sound opening principles" but quickly gets clamped because what the hell is this c5? Free pawn? And soon loses position and the game to his opponent's...ahem...opening preparation.

He goes back to club, asks coach what is a Ruy Lopez? Oh, it's an opening, but don't worry about that now, let's work on setting up knight forks and back rank mate patterns.

You get my drift. 

Except that never happens, and your example is really weak if you don't give the moves of such an encounter.

If he knew opening priciples, he would know that it's not a free pawn, because capturing would give up central control. Then he can see that the opponent can play e3, opening the bishop so developing while attacking the pawn. So he will have to make another pawn move in the opening (against opening principles) to protect it. So he thinks - maybe pawn grabbing in the opening isn't advisable (another opening principle).

Ok guys, I know you've all drank deeply of the "don't need to know openings" kool-aid that has been steadily poured for the past decade...but as you slyly look at your chess library and see all the opening books there, and as you gaze at your rating which you just know is about 500 points lower than you'd like it to be...gonna work on your endgames some more to get that up? Please. It's all about openings, from the very top to the very bottom. Yeah, of course, you have to have tactics and understand how to play the game, but in the end, what are you taking to the desert island? 1000 mates in three or the MCO?

The reason why opening books sell like hotcakes is twofold. One, compared to the rest of chess, studying openings seems really easy: all you need to do is memorize a bunch of moves. Two, people really think that having a bunch of moves memorized will help them win against people who don't!

The MCO? Sheesh, at least take an actually good opening book.

But I'd try to cheat and take all nine Yusupov books there. There are actually a few opening chapters in them!

>The reason why opening books sell like hotcakes is twofold. <

And which reason explains why you've bought so many?

Oh come on, Nick DeFirmain needs the royalties. Isn't he working at Sears now?

Are you just going to tell everyone that love reading opening books?

Because I like to feel like I'm a GM! But I haven't bought new ones in a year, and I've finally left the plateau I was on. My best games were with openings I had never read a book on.

Actually I think this is an ideal scenario and would like to go back in time and test it on myself... can't do that of course so if some parent gave me a kid to coach (and I could get a master to help or something so that I don't give bad advice) then this would be a lot of fun I think... to coach them pretending named openings don't exist.

I think they'd crush their peers who spent time memorizing Ruys and Sicilians.  By the way the queen's gambit accept is solid and I'd say there's a very very good chance it would immediately take a scholastic player out of his prepared lines... in fact that's what would happen in nearly every game.  They'd play an OK move that takes their opponent out of book early and while the opponent feels confused the non-opening player is comfortable regardless.

I've done this myself my last few tourneys and it's enjoyable.  I try to leave book early with a logical move and just play chess.  Maybe my opinion would be different if I were facing masters but it seems to be completely doable at my level at least.

Skill. Na, it was the 2 bishops!