Can you translate them into similar services your business might provide? One piano tuner I know always books the next appointment--even though it may be four to six months away-before he leaves a tuning. He's locking in business rather than leaving it to chance. Can you use a "pre-booking technique"? The salesman who sold me my car knows exactly how old it is, and he sends me a "Hi, how are ya?" card every year or so. As the car ages, the frequency of the cards increases. Would this same timed approach work for your product?