The one I see takes off a week (I guess - she may just cancel on certain days) about every two or three months and then sometimes 2-3 weeks in a row. I usually cancel too so they end up in two week blocks mostly. The woman only works 3 days a week so I do not know if she cancels the whole week or not. There is usually no rescheduling because I will not go to an appointment when her dog is at her office and there are not many different days or times to begin with.
I hate how the woman tells me a couple of weeks in advance, like if she tells me just the week before I won't be able to handle it or anything. But then she will write me the day of the appointment and tell me her dog is going to be there but will be picked up in the middle of the appointment. So that cancellation becomes blamed on me for being unwilling to have the dog and interruption. I don't mind her not being there, I do mind being manipulated.