Depends on the gig - anything from none to five.
I have related this story elsewhere but I think it's particularly apposite here:
Some years ago, I was playing a very cool/prestigious venue in Manchester with my originals band, and we'd just released an album. Very excited. I took my Signia and put the drums up on the stage.
The engineer came over to me:
Engineer: Hiya, I'm *Engineer* You the drummer?
Me: Yup, hi my name is Stu.
Engineer: How many toms do you use?
Me: Five.
Engineer: No how many toms do you use?
Me: Five.
Engineer:
Me:
Engineer: Mate, HOW. MANY. TOMS?
Me: How many would you like me to use? *Looks at pile of toms in cases on stage*
Engineer: Well how many do you use??
Me: FIVE *points thumb over shoulder at pile of toms*
Engineer: Oh. seriously? I thought you were taking the piss. I'm not sure we have enough mics...
Happily, said Engineer got me the BEST drum sound. She was brilliant, and was actually happy that my bass drum had no padding in it.
So yeah, five mostly. But sometimes none.