“I encourage everybody to have two pairs of shoes,” says Jon Clemens, former track and field and cross-country coach at Columbia University. The reason? Compression.
“Even with new advancements in running shoe technology like different types of EVA foam, shoes have memory, and they get compressed,” Clemens says. “If you can take them off and put on a different pair of shoes, it’ll give your shoes the maximum amount of time to decompress.” And you want the midsoles to decompress so they’ll provide the best, most even cushioning and protection, because patchy cushioning and reduced shock absorption can lead to injury.
Clemens recommends switching shoes for every run. He writes E and O on his two pairs of shoes—E for even days, O for odd days, so he’ll remember which pair to run in. (He advocates buying two of the same brand and model of shoes rather than two different kinds for consistency.) Other runners buy their two pairs in different colors, and write the date of purchase directly on the shoes to keep track of the shoes’ age. Six months, Clemens says, is as long as you should keep any shoe that you’ve run in consistently.
“It’s not like the shoes actually last longer,” Clemens says. “They’re still only good for four to five hundred miles.” If you don’t keep a training log, Clemens recommends flipping your shoes over to examine their wear pattern—if the tread is worn down, it may be time for a new pair. Similarly, if you see wrinkles in the sides of the foam that don’t go away after you run in your shoes, they may be due for replacement. “Even if the upper’s torn and ratty,” Clemens says, “it’s usually a good indication that the shoe’s on its last leg.”
Clemens realizes that shoes are expensive, so if buying two pairs to rotate is beyond your budget, there are a few things you can do to minimize your shoes’ compression, including running on soft surfaces, and only wearing your shoes to run—not to walk around or run errands.
THE BOTTOM LINE: If you can afford it, rotating your shoes will keep them feeling fresh for every run by allowing their midsoles to decompress so they’ll provide the maximum amount of shock absorption and stability possible.