For years I did without one but several years ago, I bought my first chronograph and can't imagine reloading now without one.
Whether you are checking factory ammo in a 3.3" barrel .45ACP (like in the photo below) or working up a 40 gr V-Max .223 Rem round for your favorite varmint rifle (like in the other photo below), you can't go wrong using a chronograph. Like L2R said, make a small change in your load recipe and see how it impacts your velocity, SD, etc. Get one now!