Organizing electrical extension cords when not in use. Save empty TP rolls. Fold your cords in lengths of 8 inches and insert each one in an empty TP roll. Write on the outside of the roll with a permanent marker the length of the extension cord inside of the roll.
I need a fairly good supply of sturdy cardboard boxes for mailing in my business, but I was often inundated with the wrong sizes plus too many of them until I began saving boxes by nesting them.