On average, a garbage disposal can last anywhere from 7 to 12 years, with many models functioning well for about 10 years. With heavy usage, a motor may last a minimum of five years, while grinding plates will wear down over time. It's generally a good idea to consider a replacement if your unit is approaching the 10-year mark. Other signs that it's time for a new disposal include frequent leaks, persistent clogs, lingering odors, lack of power, or unusual noises. If your unit is not that old, it's worth investigating if a less expensive part, like a rubber seal or a loose hose, is causing the issue.

If your garbage disposal powers up and you can hear it hum, but the arms inside aren’t moving, the problem might be a stubborn clog, a build-up of grease, or a jam of the impeller plate. To troubleshoot these, ensure your unit is off and disconnected from its power source before checking inside the drain or attempting to manually rotate the impeller arms or plate from the underside of the unit. A hex wrench can help.

While the drain connection for a garbage disposal is nearly universal and fits standard sink drain holes of 3 1/2 to 4 inches, the size of the disposal unit itself is not. You must have enough space in the cabinet underneath your sink to accommodate the disposal's housing. A larger model may not fit in a compact cabinet or if the existing plumbing is arranged in an unusual way. Before buying a new garbage disposal, measure the available space under your sink. If you are replacing an old unit, it's often easiest to choose a new model of a similar size.

Your garbage disposal will only affect the health of your septic tank if you’re using it too frequently, or filling it with organic waste that doesn’t fully break down. If the tank fills up with too many solids, the bacteria won’t have enough time to consume it before more is added, which can lead to an overflow in the drain field. Your tank will need to be pumped more frequently with excessive or improper garbage disposal use.