Working on a steeper roof in my last house, I tied an old climbing rope (good enough for top-roping) to a tree on one side, threw the rope over the roof, and wore a harness that it was tied off to. Still stressful but workable.
These days I'll be on my 4:12 roof in rubbery shoes but it's an old-getting-older comp roof and you can just feel the sand coming off the shingles... not good. I avoid as much as I can but probably in the next couple weeks I'll be blowing all the pine needles off of the roof; we put in gutter guards but there's still spots where they get stuck a bit.
If I had significant work to do on the roof... roofing crew, I have other things I have to spend time on anyways so I figure if I'm paying for one or the other it may as well be pay for the roof, pay to cut that big tree down near the house, I can mow and build things on the ground, install or fix fences, and fix a myriad of things around the place