To know the drill is to be familiar with the usual routine. You know the drill by now.
It saves an explanation and assumes one is not needed, which can be a small compliment. The drill is military, from the repeated practice that makes a routine automatic.
1phraseknow the drillTo be familiar with the usual routine.
“Anybody who has done it twice will know the drill.”
know the drill is a phrase.
Practised in Idioms