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.
If you're not up to it, the price movements that is, better to just keep it safe in your wallet and as much as possible, if you have a day job, avoid withdrawing and use your salary for your expenses. We're not gonna be sure whether bitcoin will shoot up or go down like now so selling would depend on how you assess your needs and expenses