Sometimes is a defensive thought, sometimes its an offensive one. I'd never sell it all, but converting some to another tangible asset has its merits.
I think it is worth taking a few profits along the way.
I think it is very interesting to sell about 1-10% when you reach 1000-10000% profits.
Then you can reduce a lot of your invested capital, reducing your risks and you will fell better when the price crashes again. As you will have some capital to buy back.
You are right, this works for me as well when ever I buy at higher price I use to buy it again if the price drops as soon as the price goes up immediately I will try to average it and sell it best price, I always feel that avoiding loss is also a part of making profit because if the price goes down continuously then there are more possibilities for huge losses also we do have lot of benefits like dumping money can be avoided and we can trade it again and again.