Originally posted by Ripsnort
You need better than 2200 PSI if you plan to strip you concrete drive way down in a reasonable amount of time without having "stripes" once your finished. My driveways (about 1500 sq feet) alone take the better part of 6 hours every spring. I now wish I'd have sprung for the extra bucks to get at a min. 3000 PSI.
Most of the new pressure washers have different nozzles for different jobs, so you need not worry about stripping the siding off your house while prepping it for painting. 
Pretty spot on as is alot of the advise here. (particularly on safety)
Even 2500 PSI isnt near enough of your doing driveways,sidewalks etc.
Oh you can do it. But as rip said you will have either stripes or its gonna take you a really long time.
Basically the equivelent of trying to wash a bathroom floor with a toothbrush.
For what you want it for I wouldnt get anything less then a 3,000 PSI machine.
But as opposed to buying one.
It might just be more economical just to rent one for the couple times a year your going to use it as a semi decent one will run you $1,000 or more.
Wear boots when using them not sneakers,sandles, watersocks etc.
Its alot less painful to ruin a pair of boots then it is to blow all the meat off your toes
