More help than I expected.
I bought a dishwasher, (the third in four years), and they came out to install it. When the guy got there, he checked the water pressure in the house, and told me that it was 120 pounds, and that it was SUPPOSED to be less than 80. I didn't see why... more pressure means more water, doesn't it? well, he explained that it's probably why I kept having to get a new dishwasher. He even showed me where it said on the warrantee that you couldn't, or it would be void. Ergh! If I'd known THAT four years ago, I wouldn't have had to buy new ones.
Well, they put in the dishwasher and a pressure reducing valve, all the same day, and I haven't had a bit of trouble since.