The healthy range of frequency is roughly 3/day-0.3/day.
Now living permanently with a spouse it has settled on a higher frequency than I remember before moving out on my own. Weird stuff.
> one of the days each week I'd do it would always be Monday, and I never had any explanation for why that was the case.
Social functions, a specific food or beverages (Friday drinking night? Not to the Monday though...) on some days, travel for some.