As a teen I worked summer part-time jobs as a house painter and roofing helper. As an early homeowner I had replaced two roofs; one was a two story house, the other was a 1 1/2 story house. Was never bothered hauling shingles or dragging panels.
Today I was on a single story 5/12 roof, bare OSB decking, and had butterflies the whole time.
67 is not that old. Is there some mathematical function that makes a roof get proportionally steeper as one ages?