For me because I'm not online all day and I have an offline work. What I do is set the price I want to sell. And I'm looking at it when I'm home tonight. There is also a win.
Good strategy, the only drawback is that you need to keep the money in the exchanges instead of the wallets...
It's a good strategy if you want to avoid the hard feeling of seeing the price when falling back. What I do to decide when the right time of selling is not depending on my need. If there's a need to buy something or sustain with financial then I have no choice but to sell some of my mBTC's but if there's not I don't sell and just wait for the movement of price.