Rule Number one to owning a garbage disposal is to never put your bare hands in the unit.
Rule Number two is to never leave food in the disposal.

If your disposal is on and not making any noise or humming call a plumber right away.

John W. Hammes invented the garbage disposal in 1927. He spent one decade refining the disposal before he started his own business called The In-Sink-Erator Manufacturing Company.

Several things to keep in mind while shopping for a disposal.
1. Purchase at least a 1/2 horse power unit.
If your cooking and throwing everything done the disposal we recommend at least a 3/4 horse power unit.
2. Get a disposal that has a continuous feed which typically operate by a wall switch.
3. The larger the garbage disposal, the quieter it will generally run.