For years, my morning routine included one or two trips back into the house to grab stuff I'd forgotten to add to my bag. Then I realised the obvious solution, one that could also save me the dreaded walks from one end of my cosy apartment to the other: Just buy another copy of everything. While some instances of this are obvious -- tissue boxes, lip balm -- there's probably some extra item that you could double up on to improve your life. Here are the Lifehacker team's favourites.