My typical cleaning routine is about 3 gallons of room temp water, then about 3 gallons hot water. I add a little pump armor into the last gallon... and call it done.
I have to admit... my main pump is a graco and I swear I have put no less than 500 gallons through it... and have yet to needed to repacked. I doubt that its had anything to do with the way I clean it... more like Im just lucky, and ended up with a pump that wont give up!
Matt