Remember George Costanza's infamous bulging wallet? You know the one so overfilled with cards, receipts and useless junk that it was effectively rendered completely useless? It's funny, but it's also a reality, people generally carry way too much junk in their wallet, and it gets worse when you start getting into the general storage area of pockets. Here's an interesting look (and review) of some essential items that you shouldn't be caught without. You'll be surprised with how much you can have without carrying too much.
