Every day and stay until 5:00 or so, then head back to the house we rented to cook/eat dinner and that was basically your week. I was not a fan.
When we do it we have 2-3 dedicated “beach days where we may spend most of the day there (or maybe not) and then other days where we are kayaking, visiting nearby sites, taking boat rides, playing golf, or whatever. On some of the “non-beach” days we will still be spending a couple of hours there in the morning or evening.
We’re also eating out at least a few nights nights so we don’t feel like we are cooking all the time.
I am also a big fan of renting a place right on the beach, not two blocks away or whatever, so you can easily move from house to beach and not feel like it is a big production just to go have a sandwich.