I dont care how high it is as long as it's walkable. 3/12 or 4/12 and I am happy. That being said, drip edge and first few rows working below your feet is shady. Much happier once I can work above my feet. Current house is 10/12 and that sucks. Once you start sliding, it's really hard to get stopped. On steeper stuff like 20/12, it's often safer as you cant be lazy and have to put up planks or a hooked ladder.For $200 I wouldn't even blink twice. But work like that is fairly simple to do yourself.
Only reason I'm not planning on doing my own shingles on the higher part of my house is because I'm terrified of heights. The lower level...I'd be happy doing that