The method service delivery is going to be a big factor affecting your ability to time manage.

Here in BC, private home-based consultation and collaboration with school teams is common. Many of my home-team consults are between 3-6pm. I usually schedule additional consults with my younger kiddo's, school observations, and report writing / intervention design for during the day. I am 'active and available' for work between 7:30am-6pm; it is uncommon that I am booked for that entire interval but I am always doing something during those times. I fill the extra time with emails, reading, or I work on papers/presentations/posters. I also schedule periods of environmental enrichment, e.g., walking the dog, 15 mins of reddit / xbox, or working on a project I am 'passionate' about. Sometimes I make those activities contingent on work completion; depends on the day, the task, and deadlines.

I have found it helpful to track how I spend my working hours. For me, these measures were the first step in crafting more-efficient processes and identifying a reasonable case load.

Maybe talk to the other BCBAs in your area about their schedule and how they manage their time. I used to think that my supervisors worked 7am-7pm and was surprised to learn that 12-hour days are uncommon (sometimes they worked split days or there are seasonal 'crunch-times' e.g., IEPs in October-November). Again, keep in mind this might only be the case where I live. Also, family factors also affect work hours (e.g., many of my supervisors who are parents prefer to do their reports / emails late or super early because their kids are asleep, to each their own!).

Keep in mind that emergencies happen, or the schedule will line up to be 12 hours long; that's the nature of any consultation work but that being the norm could risk burn out. The time that you work each day is also dependent on what you are doing / working towards; having an established case load is different than starting a company, being a director, being a student, or churning-out projects. Sometimes more time is needed to get things done, but look out for ratio-strain.

Everyone has their own way of managing their day; mine works for me but it is also a work in progress and probably not for everyone. I also have more freedom in how I arrange my day because I am in private practice. Anyway, I just blew through my 15 min reddit break for today /and/ tomorrow so... back to work!