I remember of a friend who gave up his studies and went all-in on AMP coin (Synereo - if you remember the project). By saying all-in, I don't mean that he invested any money on it but all his time. He worked as a programmer for them and used to earn $300 worth of AMP each month. He did this for at least 3 years, the project did well and he almost became a double millionaire when the spike occurred in markets during 2017 when BTC was $14k and reached $20k. But he kept the coins as it is, didn't sell them when I even advised him to do so and later when the crash happened, the project itself came to an end putting all his work and savings under the grave. So, you need to know when to sell as that's too an important part of trading.
Oh my God. That gave me goosebumps. You could only imagine how hard it would have been for your friend to lose all his coins.
He lost all the time and effort. I hope he would have at least sold some of the coins.
I had a friend who did some development work for a project and was offered $10k worth of tokens.
But I advised him to take the payment in bitcoin or ethereum and then the project team decided to pay him in bitcoin but only $300.
He took the $300 in bitcoin and is now happy because the project didn't raise enough funds and hence was not launched at all.
Even I had myself held on to some altcoins for 3 years now but sold it quite recently at a decent price.
The altcoin was at $3 back in 2017 when altcoins were at peak but then the crash occured and drained all the profits.
I am not sad though since I sold it at $0.5. Atleast I got a decent amount of ether for it which I am quite sure will cross the ATH.
By this way I hope I would cover the $3 price in an indirect way and get back the profits.