This is very true, I've talked to so many contractors doing work for me who were in their 20s and already had back problems far worse than anything I've yet exp

This is very true, I've talked to so many contractors doing work for me who were in their 20s and already had back problems far worse than anything I've yet experienced (and I haven't been 20-anything for decades). To a rough approximation, all of them. I did meet an older plumber, though. I asked him about it and he said his trick was that he only did new construction, no repair. Much easier work. On the occasion he had to do any re-work, his son did it.