This, keep the lines of communication open. Email them three months from now to ask how things are going.
There's a skill that good programmers have of understanding at a visceral level what the customer is asking for and delivering that and more. But a good programmer often does this "effortlessly" which leads a company to believe that all programmers are like this, so you should just find the cheapest one. They're not all the same and companies that have made this mistake quickly learn to cherish their good programmers (whether employees or contractors).