When to sell ?

If you have been an investor since many years, chances are you would have made lot of money if u would have held on to your good stocks. The question arises , when to sell. Well it is not easy unless u had predecided goals for yourself. There are many good advisors telling different strategies, but I think the following are worth considering.
1) If you need money , then sell.
2) If your asset allocation was pre decided, sell equities to balance your portfolio. Increase your exposure to gold, debts etc.
The second strategy is best , because it minimises your risk and maximises your returns in numerous ways.