A few weeks ago, I bought my first pressure washer. A Ryobi unit for $100. Never had one before. Never used one before. I moved into my house in '02, and didn't realize until now how much it needed it.
I spray with the max pressure nozzle on the sidewalk, and now it's changed color.
I spray my brown/green stained wooden stairs to my garage, and now they are the original wood color.
I spray the awning(lower pressure) of my house, and it was raining dirt & moss. Some paint came off down to the fiberglass, but I'm going to repaint it anyway.
The difference is truly night & day.
I think the water runoff to the lawn has made the grass grow better too.