So you've been running a bunch and just realized you've clocked almost 350 miles. It's about time to pick up a new pair of sneaks. When you go shopping, it's important to think about the state of your feet. They'll swell slightly as you go about your day, from standing and moving, so avoid buying new sneakers in the early morning when your feet are their smallest. Instead, buy your new kicks in the afternoon, when your feet have had a chance to fill out. That way you'll ensure the best fit, and won't have to worry about your new shoes feeling tight.