Originally posted by @Ben Leybovich :

So - the answer is a function of the put-forth objectives - objectives that you set forth when you bought. If you can achieve desired ROI by selling now - sell. If not - hold. Don't get greedy and try to over-perform by spending money and time. Sell and take risk off the table as soon as you reach the hurdle - done.

 Great points. Some definite food for thought. I have been bad with velocity of money in my opinion (too lazy to do it well). Make it, keep it, and multiply it, as Uncle GC says :)