That isn't how violators think about it though. They either can't afford it right away so they stall, or they CAN afford it, it's just that everything else in

That isn't how violators think about it though. They either can't afford it right away so they stall, or they CAN afford it, it's just that everything else in their life takes priority over sitting down to pay the bill. Pure negligence. Any experienced contractor should have a clause that charges interest after some point. You can be "nice" about it by reducing the interest rate or extending the deadline on the next job after the client has made clear they can pay on time.