A buddy of mine had a client who was always late paying, then asked for a huge project with no deposit. He told them he needed payment to start, and they ghosted him for three weeks. When they came back expecting work, he just sent a short email ending the contract. The peace of mind was worth more than the headache, you know?
Kim188's buddy did the right thing. Had a similar situation with a guy who wanted me to build a website for his band. He kept changing what he wanted and expected me to drop everything for him. After he blew off three scheduled calls, I told him I couldn't take the job anymore. He got mad, but my other clients were steady and paid on time. Sometimes you just gotta cut the dead weight loose to keep your sanity and your good customers.