A good rule, it just can't really be helped on a flat roof. Whether you're swinging a mop (which we tried to avoid in winter; keeping the tar kettle hot can be a challenge) or torching rolled roofing, the hot-cold-hot-cold is unavoidable, nevermind the physical exertion. I'm glad I got out of that shit.
Lol, I hope they bought it back for less than they originally sold it for