OK, that’s a bit hyperbolic, but it’s certainly true that it’s saved me from having to buy a new dishwasher.
My wife has been increasingly vocal about the poor condition of our glasses after they have been through the dishwasher. The used to be sparkling, but over time they became dull and lime-coated. She was convinced that it was the dishwasher’s fault, and was going to make me get a new one. I finally decided to try some Lemi Shine, which is basically citric acid. The results were nothing short of amazing - the first batch of heavily scaled glasses came out crystal clear and sparkling. We now use it every time we run a dishwasher load.
At the risk of sound like a shill for this stuff, I highly recommend it if you have hard water and problems with lime buildup on your glasses.