Hi Steve,
If it's for a punctual job our opinion is to have a material rental company so we can have the ladder ready for that particular day.
If you are aware that you are going to need the ladder for more days, the right thing to do is to get one, because it will cost you better.
If you want to buy one, look for a reliable supplier to guarantee your safety and quality (in writing).
I hope it'll help you,
Greetings!