You hold a coin for years just to go back to it's ATH (All Time High) ? And most times majority of coins don't go back to their ATH ever again, what could you learn from this? Never ever hesitate to take profits, even if the project is the best ever, take profits, invest again when price is down because believe me, the price will surely go down
It's easy to say but you never know what is going to be the ATH.
If you look at the charts day by day they usually show the same pattern of 2 steps up 1 step down. So a coin goes $200 up and then corects $50-100 and goes up $200 up again.
How do you know that day is going to be the last one where the move up is twice as strong? You hold one more day and it's down 50%.
That's why people usually end up holding bags.