When do you sell your own company's stocks?

If the company is not as good as when you first bought it, thats when you sell. When I'm up big on a stock I always sell some, if you are trying to guess the market by selling all, you will almost always fail. Sell in parts and buy in parts. So if you have 300 shares and you are up big, sell 100 .... if it continues with a big run, sell another 100 ... then let the rest run. If it comes down and you still like it, but the 100 back.