"Get the kiddies off the street"
When I started to play this game , I heard this many times!! Pull trump. It was a rule I was told I should abide with.
Lead ♥K
Declarer Pulled Trump and went -1, most other pairs made their contract.
After the opening lead, if you stop, think and look at the hand you will see that you have 2 heart losers, 2 diamond losers and perhaps 1 club loser. Too many.
If you have followed the "rule" to pull trump, you will be down.
You must ruff 2 hearts in dummy before you pull trump.
Beware some of the "rules" you will hear are not always valid.