It depends on the expectations. If you enter into the project with an agreement that work done on time deserves money paid on time, then everybody needs to hold

It depends on the expectations. If you enter into the project with an agreement that work done on time deserves money paid on time, then everybody needs to hold their end of the bargain up. And when you get 3 on time payments, and then the 4th is slipping you have to wonder if it's because they are having trouble getting the money. If they're having trouble getting money, why on earth would you waste your time working on a project that you won't get compensated for? I think it's totally appropriate to expect on time payment if they can expect on time work. There's no reason it should be a one-sided agreement. How you reinforce that is up to you. But I don't think that communicating that their late payment is making you nervous and uncomfortable with the project is out of the question. On a previous gig, this worked well on. I started seeing issues on his end with paying on time and it was rooted in ability to get the cash. Danger! He needed the project done asap, and couldn't afford me putting it on hold as I waited for money to come through. I communicated nervousness, so he had to hustle to get the cash. Of course, once my work was done, it took quite a while to get final payment. It makes me wish I had a way of putting the design files in escrow of some sort, so that at least the pain was shared.