You need a good reason to delay drawing trumps

There is one issue that towers above all others when declaring a trump contract: Do I get rid of (“draw”) the opposing trumps immediately, or do I delay the process? There is no simple answer (sorry!), but you do need a reason to postpone matters, because there is the risk that that the opponents will trump (“ruff”) your winners.

What happened
Declarer won ♥ K with ♥ A, and was in too much of a hurry to discard his heart losers on dummy’s diamonds. At Trick Two he crossed to ♦ Q, and followed with ♦ A, (on which he threw one heart), then ♦ K. It was on this last top diamond that East ruffed sharply with ♠ J. Declarer made the best play, refraining from overruffing (dooming him to a trump loser), and instead threw his last heart (as planned). On many layouts declarer would have survived, but here East was able to cash ♣ AK (noting West follow with ♣ 8 then ♣ 4 to encourage), then lead a third club. West ruffed with ♠ 10, and that meant down one.

What should have happened
If drawing trumps had involved a quick loser, declarer would have been correct to cash dummy’s diamonds first. But there was no need here. Win ♥ A, and cash ♠ AK. Here you are favoured by a 2-2 split, but on a (more likely) 3-1 split, you would leave the master trump outstanding, and progress to diamonds, still making unless the second diamond was ruffed. As it is (trumps gone), you cross to ♦ AKQ knowing your game is secure (indeed for an overtrick). Away go the two losing hearts, after which you can force out ♣ AK. 11 tricks and game made plus one.

If you remember one thing...
You need a reason to Delay drawing trumps.