Good point concept, most jobs are just done with cold anyway.
I would say am still new to pressure washing, had my machine about 2 years and done quite a few jobs, regular window cleaning customers wanting entrances, car parks, blocked areas etc etc.
I have a job I clean in the city centre, they asked me about moving the gum, now my machine will get quite a bit of it up just on cold but I wouldn't take a gum removal job on. Anyways, they got someone in and he was there for a few hours (3 maximum ) and put a bill in for £400 ...... Got me thinking