a few years ago I was only 20 feet up on my extension ladder trimming my trees with an electric chainsaw.
I have been up on 40 foot ladders replacing 4 x 8 sheets of plywood siding on the side of chimney stacks that were only 4 feet wide... Lots of fun, especially when you have to remove the sheet, hold onto it, and reposition the ladder on the studs behind it, before you carry the sheet down one step at a time... And it was just as much fun to carry the new sheet up, pop the ladder off the studs and quickly slide the new sheet, into position behind the ladder and nail it... Lotta fun, did it for an entire summer, and I can say I can scare the boogers out of people now with my crazy ladder antics and what I will do on a ladder now and not be afraid...
I honestly don't know if I could or couldn't do this, there is the inherent fear of heights but I don't know if that would stop me from doing this... Can't say it wouldn't make my mind think twice with each step though...