Tekno nitro noob questions, using stock components.

I already stressed my first clutch bearing on my first 30 minute a-main, probably not a huge surprise. I picked up 50 or so spares from tekno and avid. I've heard that most replace every big race day or so, sound right?

Clutch shoes, bell, and springs. How often to replace? I've seen everything from one gallon to five gallons.