I never fix targets. Don't see the need too. IMO, a stock is a sell when you don't feel comfortable with anymore.
You can elect to unload your entire position if you think that there's no more money to make for a long time. The geopolitical situation or the current valuation of the markets are factors that may influence your decision (although it should not...).
There's also the option to sell part of one's position. If you still like the stock and feel that you should downsize the holdings for the sake of diversification...
The point of the specific price is my limit on when I will no longer feel comfortable (in these current conditions) with owning the stock. I actually think that having a target is crucial, if you don't know what your company is worth, how can you buy and sell it?