That's a tough question to answer. It depends so much on the individual.
If you exit now, ask yourself.... where would you park the money? What would you buy? Do you have a better stock? Overall, if you have a long term horizon and you're not an ADHD trader like a lot of folk (myself included).... I would let it ride with one caveat.... and its a tough one, but try to divine broader market corrections and pull out then. The trend is your friend. For now I thinks its on an upward trajectory, there will be some short term pullbacks which is what I am playing for tomorrow and next week. But trying to time those in conjunction with the broader moves in the averages is a beatch.
Watch the volatility daily... and when its high....sell covered calls, snag that premium, get free money, and let time decay work for you. If the stock gets called away, so be it. You can always get back in, there'll always be a pullback.