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.

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.

As with many appliances, proper maintenance is key to maximizing your garbage disposal’s life span. If everyone in your household is on board with proper care and maintenance, like running water while operating the disposal, you should get plenty of years out of your unit. Avoid putting the wrong food items down the disposal, including pasta, rice, bread, and more.

Your garbage disposal is not draining because it might have a clog due to food waste, a foreign object, grease, oil, fat, or it may have a broken motor. When water doesn't flush out of the disposal, that's a key sign that your disposal has a clog or needs repair.