I'm not a numbers person. So instead of using a combination lock at the gym, I use one with a small key. I worry constantly about losing the key. It wouldn't be a big deal if I lost it when I was working out, but if I accidentally locked it inside my locker when I was on my way to the shower, I'd have to walk to the desk in a towel and ask to borrow a bolt cutter. You'd think that the fear of losing my key would ensure that I'd stay sharp, but I know it won't. So see, every day before I ride my bike to work, I double check that I packed a clean shirt to change into once I arrive at work. Last week, I forgot to pack my shirt and had to bike back home for it. Twice.