This is an interesting thread. I always left it up to the customer up until last year. At the beginning of last year I decided I only wanted to work X number of jobs. This limited my availability obviously and I would end every conversation or email with the remaining dates and times that I have available. It basically put people in a position where they felt that they may not get a slot so they booked quickly. . I started bookings for this spring and summer and within a week I was booked through June simply because I was putting a limit on my jobs and people were afraid of not getting in.