For myself, one of the perks of opening up my own business was the fact that I would get to be in charge of my days and time off. I am the employer, not the employee, so I tend to think like that when I made and adjust my contract and policies. I don't have anything that says how much time I will take off in a year. I purposely left it open so that it gives me wiggle room if I need/want it. It hasn't happened yet but if I felt the need to take a mental health day than I could and I could still give 2-3 weeks notice of it.
During interviews, I stress to the parents how important it is for them to have back up if I am sick or take vacation. I have only ever had 3 families who had almost 0 back up help and not even they complained!! The back up care is on them though, it's not my issue. That sounds harsh but it's just the way it is.
I have almost always had parents who have had fantastic jobs. They have no problem leaving work an hour early the very odd time (many just take their lunch at the end of the day). Many, many grandparents and aunts and uncles help out too and I have met many of them because they are the ones who from time to time pick up early. IME, it is easier for a parent (or family member) to pick up an hour earlier than at noon but I close at different times depending on my schedule for that day/appointment.
The key of course, is to not abuse this power and take every Friday off or end early just because. Very quickly word would get out and your business reputation would fail. Most parents realize that we are just like them, we need time off as well and it's not fair to expect us to be open early and close late. The nice thing about our job is that we don't have a higher up to approve our time off but we do have clients that we have to be reliable for. Finding that balance is what will give you a great business without feeling like you are going to burn out!