OP is thinking too much in fiat terms. I you really believe in bitcoin, in its future, in its potential as the best safe-haven store of value in the world, you won't sell you bitcoin to "protect" your earnings from some short-term fluctuations. Just HODL.
I also agree that you can sell small portions as it goes up, as I have done.
I do understand people who think in fiat terms, but I do not get it why anyone would think small in crypto world. This is a place where your wildest dreams could happen and that is why I am in here. I am not even joking, you could start with just few hundred dollars and end up with millions of dollars here, not that it will definitely happen, there is a 99% chance it won't happen like that, but the fact is that it is more possible here than anywhere else in the world. You are not going to turn 100 bucks into 1 million dollars in stock market, you won't have that in gold, not in oil, not in anything in the fiat world.
However in crypto there is a slight chance you could invest into some altcoin that becomes top 10 coin eventually. You could have this few times and suddenly you are richer than your wildest dreams. So even if you think in fiat terms, you should aim super high, amount that would allow you to live your dreams without earning one more cent.