Here in our house we do school all year.
In fact, we probably do more school in the summer than any other season. This is because it's nearly 100° and 99% humidity for large portions of the day for several months. I keep the kids inside on most afternoons in the summer and send them out after five. It's still hot and muggy, but the sun is far less intense and its much more tolerable.
So with kids inside for large portions of each day, I learned early on that I needed to give them stuff to do. Having it be schoolwork is an easy and beneficial solution. We always have what we need, they always know what to do, or where to pick up from where they left off. And I don't have to sizzle my last remaining brain cells trying to scrape together new and appealing activities to entertain them. It also helps keep a semi-consistent routine.
This does not mean that they don't get time off. They get plenty of time off. They get days and even weeks off whenever we need/want it. If we want to have friends over, we take a day or two off. Same for if they go to a friend's house. Or if we have an outing or event planned or decide on one spur of the moment. And if we have an especially busy week or two coming up then we just take the whole time off.
I love our schedule because it allows me the freedom to grant their occasional wish of "I just wish I didn't have to do school today, I just want to play." Which is fun to get to do for them.
They've even gotten bigger chunks of vacation time periodically. Like when Kit was born, we took off about six weeks.
It also seems like it helps them view school stuff more as activities rather than something they must suffer through. If they are not enjoying it then they are likely not learning much from it. If that's the case, it just seems like a waste of all our time. And if we're going to waste time, then in my opinion, it ought to be fun while we do it!