My take? When it feels right. There's no time limit to that.
HOWEVER you should be dating because you are healed and have restored a true sense of confidence. You should be dating because you've taken the time to assess what went wrong in the past relationship and how you might have contributed or encouraged the bad behavior (i.e. ignoring signs, accepting bad behavior assuming he would never do it again, letting things go as long as they did).
YOU SHOULD NOT be dating because you're missing a warm body, "because a ladies' got needs" or because you're hoping that by finding someone new you will forget about the old.
I'm so against rebound dating cuz I think it causes people to bring past baggage into future relationships. There's no way a rebound relationship can succeed because it's based on the results of a relationship that has nothing to do with your new partner. And ladies, we are the queens of baggage.
But that doesn't mean you can't go out and have fun. Just be conscious, that you're fun isn't about a new boyfriend but is about YOU and restoring your confidence.