When you come to move, and a thing you're planning to move is still in a box since the last move, throw it out.

There's a neat little related lifehack regarding clothes that works similarly.

Each year at a good landmark point (ie, spring cleaning or 1st week of the school year if you're a student), sort through your closet and organize/clean your stuff. Then, when you put your clothes back into the closet, put the hangars backwards, so that you have to reach around and hook them behind the bar. As you wear clothes, place the hangars in normally.

The next time you organize your closet (ie, spring cleaning the year later or when the school year ends), note which clothes and still backwards and consider throwing them away or donating them. If you didn't wear them that year, chances are you won't wear them next year either.