As a frequent traveler there are some things that are always in my suitcase and that are never taken out when I am at home so I won't forget them on the next trip. One of those things is a spare charger for my mobile phones. When I recently arrived in Oxford I noticed that I forgot to put the usual charger in my backpack. Already thinking that I'd have to go out and by a charger for the week I suddenly remembered that I have a spare one in the suitcase. So much for redundancy! Sure, you wouldn't have this problem with recent phones, most of them now chargable over USB. And with universal chargers now coming to the market, things are getting even simpler and, as a side note, also a bit more environment friendly.