I used to install these for a living. Do not share the electric with other things or you risk shorting them if the motor in the garbage disposal stresses, such as if you drop a fork down the drain and it jams. You are much better off just plugging other stuff in elsewhere. Not every electrical source can or should be multipurpose, because fewer things will be affected if there is a complication on a closed circuit. Appliances will cause complication more often than any other thing you plug in, and you probably don’t want that to fry your laptop or stereo system, so they should really just get their own plug.