For first cleans, don't use a ladder, use a four inch unger scraper (the type with a handle) on the end of a pole for anything stubborn like paint or putty. But generally, first cleans do not need to be laddered. You can also explain t the customer (after you've finished) that it may take a clean or two to get them perfect. I've never had a problem with that.
And for gaining access on flat roofs, I use a short lightweight domestic double ladder from B & Q; probably not the most professional ladder to use - hands up - but it doesn't get used that much.
I know a couple of local guys who don't use ladders at all; and I think I'm going to evolve towards this.