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.

Never put glass in the garbage disposal. It can damage your disposal or eject shards of glass out of the disposal and cause injury. If you get broken glass in your garbage disposal, turn it off and cut the power from the breaker, use a tool like pliers or tongs to remove the glass, and use a wet-dry vacuum to remove the remaining glass pieces. If you can’t access the disposal safely, call a garbage disposal repair pro.

The main issue with garbage disposals is clogging. This can mean a clogging of the pipes that expel the food along with water, or a clogging of the mechanical parts themselves. The problem lies in the solution because you can’t easily see clogs if they’re inside the system, and reaching in to dislodge stuck items is a risky proposal. Call a pro and ask what they would do, but if you can’t see the clog easily, and running the unit won’t free it, you need to let a professional handle the fix. 

While unplugging your garbage disposal and plugging it back in may help, most units have an actual reset button, a bright red switch found on the underside of your unit. If your garbage disposal needs resetting, you may notice this button sticking out about a quarter of an inch from the surface of the unit, with which it’s usually flush. Simply depress this reset button to reset the unit, and then test to ensure it’s working about 10 minutes later.