I should have mentioned this in the original question. I always work on a milestone basis. In addition to the initial contract, every piece of work is done some

I should have mentioned this in the original question. I always work on a milestone basis. In addition to the initial contract, every piece of work is done something along these lines (obviously abbreviated): Here's the work that I will do for this milestone. It will take me approximately x days and cost y. I then get the client to sign off on that before commencing work. This make sure that I get paid for work that I do on a regular basis. If the client doesn't pay on time for the last milestone, then I stop work. It keeps everyone honest.