Very good question. I am a custom installer and have recently instituted an extended warranty program. We did it mainly to reinforce the fact that service is not free lifetime. If you are semi-knowlegeable, you should be able to perform routine maintenance tasks. If not, and a lot of people aren't, then a maintenance contract may make sense. I would not buy one from the large chain stores, however, as that is not maintenance, but merely insurance. They generally will not perform routine maintenance that would extend the life of your product.