It may appeal to a dark side of human nature, and I may be enabling the worst to come out in some people, but my experience is that down payments to many types of contractors end badly. I see folks take the money and run. Take half down and then consider the last half to be too little compensation to even proceed further. At the best of times, the completion date is doubled or even quadrupled. Some things never get finished. Many get buried in some dusty corner, to be gotten to "someday." Few seem to consider the contract from the side of the consumer.
Meanwhile, hides get old and dry, or too long in the freezer, maybe unskined so long they mummify in the freezer, or the hair eaten by mites or whatever the cooties are that attack fur. I don't know anyone who has had their completion date even approached, much less honored who has paid in advance! What good does it really do? I only make it financially possible for them to skip out to the next project. I wish I would ever learn, but like a dummy I hand it over in my enthusiasm.
Prove me wrong!