That is a good concept.I tell new clients i need half of the cash for me to even start.
I got burn one time, (well dint loose it was more of a principle ) a lot of the stuff i do is by word, dint loose my work i was able to profit. If you ask for half upfront it motivates you to do a fast job job plus you just did a sale. Nice!
The sad thing is some big accounts on bhw don't reply to you. I was scammed of an amazon niche site which I had to pay for my own hosting and domain