@NC-Retired
Questions... how long does this maintenance take? Minutes? Hours? Frequency?
Unanswerable for a general case. As to myself and attending a single broken nail on demand, that's entirely defined by the logistics. The action itself is literally single movement -- seconds. If I decide to do all other for once, or say, look at them before going out and decide they need attention, perhaps fifteen minutes. Unless, going into full manicure mode (have done that too, especially when I presented feminine for a few masquerades in my teens).
Or... once in a while I polish my thumbnails. Literally, not applied polish, but usig progressively finer abrasive polish the surface of the nail itself. That's a rather lazy time affair, it take a while. Anyhow, there's no definitive schedule, happen by demand or whim. Once two-three weeks is perhaps minimum demand for a basic cut.
Toenails I typically do after bath, but not every time, so perhaps similarly.
What I am trying to come to grips with is the amount of time that an ancestor of 500 to 5000 years ago had to devote to personal care and cleanliness.
Entirely defined by the culture of the people in question.
My answer?
Two to six hours once a week, when we talk about deliberate, regular, general washing.
I believe that's a rather healthy base assumption, but it may, and did, vary wildly. My answer is based in north-east European sauna culture among working class.
The pre-planned sauna was heated one per week (with may or not have been 9 days long pre-christian times) and the best part of that day was dedicated to the sauna ritual. That was the primary means of general body washing, but doesn't include functional washing (like, hands, face, genitals (especially for women) or necessity after especially dirty work or alike. Nor, swimming. Weather permitted, that could as well be daily during the warm season.
(The sauna process itself, on demand at other times, or in modern setting, that typically take about one and a half to two hours, although can be rushed down to fourty minutes, or extended pretty much indefinitely.)
In medieval western Europe there was a religious stigma against washing (because of the badly contaminated surface waters in cities) and people didn't do it, presumably. And I mean they did not wash (at least not in modern sense) at all for months to years. It's less awful than you think. Washing is, up to a point, entirely optional. Body pretty much clean itself given a chance, within limits. I have myself lived for over three months without washing and thus can give some pointers how to manage in such a situation. (Like, being sweaty is an opportunity to scrub off dirt with a rag.)
And that's why French royal curt changed clothes up to six times a day. (It's hard for us from the age of mechanization to wrap the head about how expensive it was... with each outfit priced in order of a new car in modern money, that's like million $$ a day in clothing for the certain king who ostensibly never reused them... well, he was that rich.) They also consumed ample amounts of perfume.
And of course, it doesn't mean those people didn't have their own toiletry rituals. How much time those took, that's almost entirely their own choice.
As to actual toilet... again, it's mostly defined by the logistics of the act. If I sleep in the attic of the house and go pee outside behind the barn, time spent walking wastly exceeds the time actually urinating. Same with defecation. Finding the place/opportunity for that is most of it, beyond that it's perhaps less than ten minutes a day on average. Anything between twice a day and twice a week is considered normal.
By person experience, it is possible to go three days without peeing and up to a week without defecating (especially if one doesn't eat too much, if at all, at the same time).
So, I would say, a superhero on a mission never doing anything at all of it isn't necessary that unrealistic, up to a point.