IMO, doing work with no money collected up front may be ok with trusted contractors but its still a risky way to do work.
I once subbed for a pretty regular contractor, never took anything upfront as he always paid for materials and I got paid when done. Great guy. He was spot on for a few years and I did about 10 decent sized jobs for him.
Then I did one job and he avoided me once I was done. I did some hunting and found out he went belly-up broke. Once I pinned him (I waited at his house until he pulled in his driveway) he told me was broke and filing for Chapter 11. He had no money to pay me. I was out $8k. All I got from him was "Sorry,man."
My policy now is 50% upfront. And I don't budge on that.
I've been burned for a similar amount in the past as well, on an addition/remodel. BUT, on a new construction, such as this thread, I have no idea how you're getting money down when there is a construction loan and, presumably, a title company involved. The job of any title company is to ensure the HO and bank don't get burned, why would they offer 50% down just for showing them a paper contract? No offense, but I've never been burned as badly/often by a homeowner as I have been from another contractor/builder.
I guess if you're doing a bathroom remodel for "Tommy & Sue Homeowner" in booming times you'll get away with collecting 50% for doing virtually zilch, but when you're doing larger residential/commercial/industrial/government type work, you can expect to get absolutely nothing down until you actually perform some kind of work. And even then, don't expect to get it immediately upon completion....