I really do not have a good idea what you are driving at but if I want to assume, I would say you are referring to selling your assets for profit. If you are holding for a long time, this is not the best approach except if you are a regular trader and you know what you are doing.

Looking at it from the lame man angle obviously like you (no offense), What if you sell today and it keeps rising tomorrow and it never comes down back to that point you bought it again? You better just keep holding mate! and if you want to trade, there are better ways to go about it.