I can't recall all the talks with my legal guys, but I never use the word 'contract' - it's always 'an agreement'. I have a production agreement. You spell out a scope of work, timeframe, responsibilities from each party and get signatures. It also helps to build in enough profit and reasonable assumption that changes ARE going to happen outside of this scope. With the right amount of money, you can happily say "we'll take care of that". But definately say 'here's when it's done.'