I am on a mission to start more DIY projects around the house. Our 18 year old Kenmore dishwasher stopped cleaning things gradually over the last few months. Finally it got so bad that we thought we needed to replace it. Just for the record, we have three kids and run ours pretty frequently. Hand washing (as I'm sure someone will suggest I do instead of using a dishwasher) is not something my DH and I want to spend a ton of time on.
I started researching new machines but noticed that reviewers kept mentioning removable filters. That peaked my curiosity and prompted me to search the internet to see if our older machine had a filter. Sure enough, several videos popped up showing me how to disassemble the bottom interior section of the dishwasher. Honestly, until I found the videos, I had no idea dishwashers had filters.
Once disassembled it was easy to see it had likely never been cleaned or had not for many, many years. We've only owned our home for 4.5 years, so definitely not since we moved in. Complete nastiness was in the filter and adjoining parts, including pieces of chipped off plate, a few small rocks (I blame my children), a plastic bread clamp, and some other assorted material. BUT once I cleaned everything out, reassembled and ran an empty load with a little vinegar, our dishwasher now cleans dishes again!! It also sounds far more powerful.
So take note that if your older dishwasher stops cleaning well, instead of giving up on it, try cleaning out the parts at the bottom first!