Yeah, i agree with yours idea that we need to withdraw the profit whenever its possible. It's really hard for us to hold a coins for 3-4 years for break even, so withdraw 50% profit and keep 50% to hold is the best option with those want more profit from a coin.
Taking profit should be done if you need to see how much you've made and there's a way that you're going to spend that money.
That's a good idea to take profits but don't make yourself empty by just taking profits. You can take a profit of yours with a few portion of your total holdings but don't let yourself have nothing left because of it.