Trading Bishops and Knights?

Hey everyone.

I was just wondering if there are any theories or rules of thumb about when your supposed to pull the trigger on Bishops taking Knights, Knights taking Bishops, Knights taking Knights or finally Bishops taking Bishops?

I know that a lot of these types of moves are situational or theory/line dependant, but I'm just wondering, for a beginner like me, are there any situations were I should be thinking, "Oh that's an auto-exchange of 3 points" or "I'm better moving that piece and saving it for later".

Some examples I can think of would be:

1. If you exchange these pieces but in the process force a doubling of pawns that would a be pretty solid time to exchange.

2. If you ruin a Castling ability by forcing the King or Rook to take your piece to pull off the exchange.

3. I tend to be more protective of my Light Square Bishop when playing White and my Dark Square Bishop when playing Black as they are more valuable than their couterparts. This is correct?

So are there any other situations when it is an auto-take with these pieces? Maybe a few knowledgable players could give an example?

I guess what is confusing me is that they are both worth the same amount (3 points) but are better in certain situations, and so I just need to understand when it is better to keep these pieces for later, or go a head and just scarifice my own for my opponents.

Thanks.

Bishops tend to be better in open positions, knights when the pawns are locked.

Also, the bishop pair tends to be an advantage over bishop and knight or two knights because of the advantage you have on the colour squares of your opponents missing bishop.

Bishops are normally better in endgames when there are pawns on both sides of the board because the knights are so slow to cross the board.

If you're going to an endgame with an extra pawn or couple of pawns, it may be better to keep a knight than the opposite colour bishop to your opponent as a lot of opposite bishop endgames are draws. And vice versa, you will have more drawing chances if you can force your opponent into an opposite bishop endgame.

Knights are better in centralised positions (control more squares) andif they can have an advanced point up the board where the opponents pawns can't challenge them, especially if the opponents bishop of that colour is missing. Bad if they are away from the centre without many squares to move to.

Bishops are good if they control long diagonals, bad if they are stuck behind your pawns, especially if the pawn structure is quite fixed.

Obviously you're always willing to trade if it will give you a winning pawn endgame, whether your bishop/knight is good or bad.

From my recent games, move 37: Good vs bad bishop http://www.chess.com/echess/game?id=61008184

From move 22, black's knight is terrible. http://www.chess.com/echess/game?id=61000890

Scott hit it right on the money, I was going to write something similar, but no sense in repeating it. I'll just add my two cents by going directly with your three examples:

1. If you exchange these pieces but in the process force a doubling of pawns that would a be pretty solid time to exchange. I've heard that doubled-centered pawns can be stronger for a player given certain positions, so calling it a solid time to exchange could be precipitous. I tend to go for it when I can double outside pawns.

2. If you ruin a Castling ability by forcing the King or Rook to take your piece to pull off the exchange. Yes, although remember that castling isn't always necessary. If you and your opponent went through exchanges at the beginning of a game, and this particular exchange would cause the king to move in a game with little or no minor pieces left, it wouldn't have the same effect. Exposing the king is good when you have peices on the board to attack him, otherwise it may help your opponent be one step closer in positioning his king for certain pawn pushes.

3. I tend to be more protective of my Light Square Bishop when playing White and my Dark Square Bishop when playing Black as they are more valuable than their couterparts. This is correct?
I've heard the same, I guess it depends on the opening, certain openings control certain squares, so it would really depend on your planned attack, I think..

Good examples, Scott..