I keep waiting for the "slow time." If anything, I would have to say July/August, but only in my Corporate gig. I schedule for 3 - 3-1/2 hours every other week at a major Sportswear company, and last year those visit lengths were not fully utilized for about 3 visits. I doubt it will happen this year though, I'm told there's a huge waitlist. I could probably bring in a second therapist. maybe.
I've talked to lots of therapists in my area and they tell me that the one week before and one week after school starts from any vacation, can be slow. Since my practice is full +, I decided to just preemptively take a week off during those times. So my plan now is to take the first week of April, last week of August and the week between Xmas and New Year's, off work and out of the office. Even if I don't go anywhere, I just shut down.
I had a slow week at the beginning of this month, I ended the week with 3-4 unfilled appointments, that was weird but welcome. I'm tired.