I generally do get up around 6 or 7am in the morning, but this is because I tend to workout first thing. Now I have sometimes accepted 8am or 9am appointments in the past, only to be let down, they get caught in bad weather/traffic, or simply don't let me know they can't make it. Whilst this is often part and parcel of any appointment system, I've then moved my day around to be left in the lurch and probably not be able to fit in personal time later on. Result is that I generally will not see anyone outside of certain hours in order that I can plan appointments, and my time properly.
The first appointment of the day assumption is, I agree quite difficult to predict. I quite often may advertise availability from 10am but my first actual booking might be 11.30am. Some days my bookings are skewed towards morning and afternoon, other days afternoon-evenings and sometimes I there might be a gap of say 5 or 6 hours where I don't see anyone between 2 and 8pm because I've had a full morning and have a regular booking in the evening.
One foible I have is that if I've had a long period without seeing a client, I am not very good at getting ready. I tend to put my feet up thinking I've got plenty of time, then suddenly see the clock and realise I've 10 minutes to bath and put my make-up on. Whereas if I'm already on a 'roll' I'm up and about getting ready already.
I allow at least 1 full hour between [incall] bookings, not for lack of offers though and often do turn away guys who have asked me to see them back-to-back. To me that just isn't acceptable, and as an indie I am able to decide upon how I wish to see clients.