I bought a pressue washer last year and started pushing for it, but to be honest, this is in my opinion, more hassle than its worth. Messy hard work, and i found out the hard way on a few jobs that pricing can be difficult.
Ive sold it now, and just concentrated on window cleaning. It works for some but not for me. Done a few inside concerv roof cleans lately, they're hard work but good money.
Stick to what ya know i say!