Yeah, DIY jobs definitely take longer than a pro would. It would probably be too costly to rent a lift for a week. The way I usually decide to DIY or not is to figure if I could do the job twice and still at least break even compared to hiring it out. I also consider the likelihood or serious injury or death. I'm clumsy, so when I need a new roof, cost doesn't even enter the equation. If you end up using scaffolding, get some rope to make a handline and have some help on the ground, at least when you start working. Climbing up and down everytime you need another tool sucks. Just make sure they're clear of the work area in case you drop something. They might look silly wearing a hard hat, but a $5 hard hat vs a cracked skull is a good bargain.