50% deposit/expenses and 50% upon completion (not necessarily after final inspection). Or sometimes it is 50% dep./exp. and 25% when "substantially" complete, 25% upon completion. If anything fails inspection I would have to go back regardless if I'm paid or not if I want to keep my license (I tell this to clients who question my terms).
But this is for work where I DICTATE the terms (like service calls, residential stuff, the RAC's, etc.). Often I cannot dictate the terms but am bound by the GC's terms or sometimes the Restaurant is Corporate owned and I have to let it go through their offices, etc.
I usually mark things up higher when I know I'll be waiting 30+ days. It happens all the time and I have yet to be screwed over; I've come close but I don't let them get away with it.
Other commercial work, you are at the mercy of them. They even withhold 10% retainage on every payment. It is not uncommon to be completely finished with a store in a Mall (for example) and still not have received a mobilization check (!) not to mention even temp. lighting, etc. But, you always get paid eventually....atleast I always have.
I suppose when the economy goes bad though, you really need to watch it.
It is standard procedure for us to put a lein on anything over 50K IMMEDIATELY! Because the first with the lein is the first to get paid if anyone goes bankrupt on you.
I did a house last year that was $160,000.00 electrical! No, I'm not kidding! That was a HELLUVA house!
I slaped a lein on that puppy the day we signed the contract. This job was broken up into thirds for payment PLUS I got a TON of extra's which were paid as we went (like 100KW emer. Gen., Automatic Transfer Switch, Home networking center, etc.).
I guess it really does vary on what you are doing (the deposit you get).
:~)