I do:
40% the day I start rough.
30% after completion of rough, not upon rough inspection.
20% the day I start finish.
10% after completion of finish, again not upon final inspection.

Any add ons or extras have to be paid in full before I do anything.

I always get a payment before inspection or I don't call for one, this is the one of the ways to ensure I will get paid. And if all else fails the only thing I lose out on is my profit( 10% ).

Jim