You lacked the "if" statement. What if it didn't skyrocket, instead it dropped drastically.
What if the price stayed lowered for a long time? What if... All what ifs.
We should watch out for that always.
Holding can be risky if price goes down in future and it will waste your time as you need to hold them again for higher price and no one exactly knows when it will boost up again after falling down.
yah botton line I sell then when it goes bellow 550-500€ to make some fiat. But I really think holding to BTC is the best option.
If you don't want to experiment with your coins and if you want to play safe then best choice is to hold them and sell when you see higher price allowing you to make good profits.