For the 1,976,545th. Its not all that easy for the customer either. Cancellations suck (for both the provider and the customer), between family commitments, work, and me time I have very few windows of opportunity to play in a given month. I put probably too much thought into a session before hand (I have some OCD tendencies), but generally I just look forward to being able to be with another person in an intimate setting, as I find it to be a respite from my hectic world. So when I get crickets or a cancellation on the same day of an appointment it's disappointing and difficult to move on to the next.
To combat this I schedule appointments usually about a week in advance and I try to confirm around 24 hours before , so that if an appointment falls through I have some opportunity to find another provider at a mutually convenient time.
I tried to find a better paradigm, about a year ago I entered into a monthly arrangement with a Lady. I dutifully paid the hourly rate plus a little to end up at a round number at the beginning of each month in exchange for a few hours over the course of the month. When we started out appointments were generally the same day/time of the week and if we missed a week we would just make it up the next. Then she started cancelling the day of the appointment. I should have been more assertive and asked that not happen, but I let it go and chalked it up to life happens. I kept up my end of the bargain but the cancellations started with increasing frequency and it ended up in a situation where she was cancelling more than we were able to meet. When I tried to communicate about it I was accused of not being considerate of her time.
I tried to tack and took the approach of how about you tell me when you can get together and I'll do my best to make the appointment happen. Ultimately it took me four months to finally collect the account. So that paradigm was no panacea either.
Communication is a good thing and it helps keeps uncertainty to a minimum. I am a professional who has nothing to sell but his time and realize that circumstances arise that cause cancellations and trying to work with multiple parties' schedules is similar to herding cats.
Customers and providers should be considerate of each others time and respect the efforts required in this thing that we do. Ultimately, cancellations are a hobby hazard.
Good luck and have fun!