I have in the past 3 years used more product Warranty's than ever before. In the case of my dishwasher I was able, by having my receipt handy, to show the authorized repair man the date that I had purchased the machine. The new motor it needed was covered and we just paid labor costs.
A savings of Hundreds of dollars. This also happened with our Recumbent Bike. I try to buy good quality things but sometimes they break. I now make sure to fill out the warranty card. I didn't for the bike but they let me do it after it broke by sending a copy of my receipt. Keep them handy.