LOL.
Fortunately all my buildings are single story.
However there are some roofing surfaces I can't walk on... like the enclosed breezeway between the shop and the garage. It's got corrugated aluminum roofing, but it's supported only by well spaced (like 4 ft) purlins below, and while the peak is reinforced and can be crawled upon, the majority of that roof would dent and probably cave in if one were to try to walk on it (although the raccoons and possums have no problem). Adjacent to that is a carport with a shed roof, and that's covered with corrugated plastic panels. There is more support below for that, and I can walk on 2x8 plywood sheet I lay down across the purlins, which I must do to clean the gutters between the breezeway and the carport as well as the gutter at the low edge of the carport. Neither can be accessed from below. So it helps quite a bit to have some sort of leaf screen up in those areas, as well as along the shop roof gutters where the trees I planted more than 10 years ago are now dropping crap all over the place.
The main house has a cedar wood roof which tends to shed bits, so I have to get on a ladder and clean out the downspout escapes at the start of the rainy season and generally at least once more. There's another shed roof off the house that covers an enclosed patio-kitchen, but it can be walked upon. There is one troublesome custom made gutter arrangement over the side door on the house... the previous owner put in a very small shunt between the roof extension over the small porch and the main downspout. That will easily clog up with cedar bits or even bits of moss, so it's one of those areas that needs extra attention.
Someday I'd like to live in a quonset hut or a geodesic dome with NO GUTTERS. LOL.