Depends on what brand of tire you use, and how you skid, also I think your gear ratio matters also (higher ratio=less friction vise versa).
I usually resist the pedals when I can, but I'll skid when I have to (emergency, getting lazy, shed speed quick)
It also depends on how you skid, long skids burns the tire faster; short, quick ones will conserve the tires.
My tires(Vittoria Randonneur, Continental gatorskin) usually lasted about a month-month half, but that's daily riding with a area with heavy traffic, and one steep hill.