Tons and Tons of good advise,
great safety tips and often overlooked tips to keep the equipment alive longer.
Three pages of it.
And nobody mentioned the airfilters.
Mostly you think about them when you're done with a particularly dusty area (you do, don't you?), have you ever checked them after a day plowing through dandelions?
A little 12V plug-in compressor may be enough to blow them off between jobs if need be.
Also, I'm not sure if anybody got Double D's questions about whether or not to pressure wash equipment. I believe rinsing with a hose is better as pressure tends to push debris where it really doesn't belong.
If it ain't broke you aren't trying hard enough