I noticed my dishwasher wasn't doing a very good job getting my dishes clean anymore. When I'd empty it, there'd still be particles of food on the plates and flatware. It was starting to get scary because I have never lived without a dishwasher. Fortunately, getting it back in tip top shape was very easy.
When the dishwasher was empty, I simply poured one cup of white vinegar into the bottom of the machine and loaded a measuring cup with another cup of white vinegar in the top rack. (It's hard to see in the picture, but basically just fill a cup with vinegar and put it in the dishwasher right side up.) I ran the dishwasher like this and now my dishes are coming out all sparkly again.