Random Ratchet Question

[NateDogg]

I'm a autobody apprentice and i'm taking advantage of the 50% discount from Mac tools. I'm going to buy a 1/2" Ratchet. My question is how many teeth should the ratchet have 30, 45 or 72? I take it you wouldn't want to apply to much torque to the 72 tooth ratchet? or should 72 be able to hold up against a bit of torque, like removing and installing boxes and bumpers on trucks possibly with rusted bolts?

Then again i haven't used the 1/2" ratchet i have right now to many times yet. And i'll probably also buy a 1/2" breaker bar. I just want to make sure that if i end up applying a little bit of force to a 72 tooth 1/2" ratchet that i wont end up stripping all the teeth in the thing.

Thanks, for the input.
Nate