The typical garbage disposal lasts about 12 years, provided you use it as intended and take care of it. Misuse may cause some of its parts to wear out prematurely. No matter what the brand or model of disposal in your kitchen, the owner's manual explains the ideal ways to use it, as well as things that should not be placed in the disposal.
Average Disposal Lifespan
The typical garbage disposal lasts anywhere from 10 to 12 years under regular conditions -- regular meaning using it in the way the manufacturer intended. The owner's manual explains the ideal operating method of your particular disposal; failure to follow the suggestions may result in a voided warranty or in premature failure of the device.
Lifespan Vs. Warranty
Even if the disposal lasts more than a decade, there's a good chance the warranty will not. Some garbage disposal are under warranty for only a few years; any problems that arise after the warranty period require repair or replacement at your expense. The warranty span varies greatly from one manufacturer and model to the next; two to seven years is typical for a warranty, although at least one offers a lifetime limited warranty. Even if the disposal is still under warranty, any proof of misuse, such as grinding nonfood objects in it, even if by accident, may void the coverage.
Extending Its Life
Using the disposal the way it was intended helps prolong its useful life -- it isn't designed to handle all the scraps left on plates or in pans after meals. Discard or compost the bulk of the food scraps before rinsing the dishes over the disposal. Avoid putting grease or sticky, starchy foods into the disposal, as they may cling to its sides or even expand inside the chamber. Cold water helps prevent grease from sticking inside the disposal -- hot items may liquefy greasy, fatty items temporarily, until they cool and cling in the disposal, potentially causing clogs. Remove food particles stuck inside the chamber by running small ice cubes through the disposal.
Improper use of the disposal may significantly shorten its life. Animal bones, even if small, aren't meant to be chopped in the disposal and may dull its blades. Firm items such as popcorn kernels may also dull the blades or lead to blockages. Avoid putting anything other than biodegradable food-based items in the disposal -- small bits of paper or plastic, for instance, could clog or damage the device. Cooking grease also isn't meant to go down the disposal or in the drain at all.