There once was a time when sneaker history was linear, when a style came out once, was on shelves for a year or so, and then disappeared, never to be seen again. Well, that time is over and done with. Nowadays all sneaker eras co-exist comfortably, with shoes from the '80s sharing shelf space with those from this year. And once a model is gone, you just wait for it to come around again. Even 50 years from now, you'll probably still be able to buy that pair of retros you picked up last year. Stick around.