Swap Pieces if Winning
If you are up material in a chess game, if you have some extra pawns or an extra piece, an easy way to win is simply to swap pieces until you get to an endgame. This is especially true if you have an extra piece, because you can swap down to an endgame where you have a piece, and your opponent only has pawns.
But the winning strategy also works if you are only a pawn or two ahead. It is easier to win with extra pawns in the endgame. An extra pawn in the middlegame is actually not that important, but their value increases the closer you get to the endgame. The endgame is where pawns get converted to Queens, and hence pawns have more value later in the game.
The more finessed version of this strategy is swap pieces not pawns (if winning) or alternatively swap pawns not pieces (if losing). The idea is to swap pieces to an endgame, but you dont want to swap too many pawns. Endgames with pawns are more drawish because you need to have pawns to promote into extra queens. You need to keep the pawns in order to turn them into Queens.
Related Chess Tactics
Read more about these related chess strategies: