It looks like selling your crypto for money when they are profitable is more safer than holding them for long, my point is only very few coins are worth holding for many years, if you still doubt about this go on coinmarketcap and look at most coins that came into this world in 2018 many of them have no volume again, the shocking one to me is gowithmi, a project that my elder brother praised so much at the time but today it's volume is not up to 50k, many projects will face same fate, be smart
So far I have been monitoring some of the coins on
https://coinmarketcap.com I see that altcoins are already very much traded in the crypto market. I myself have also concluded that every altcoin is not profitable if it is held for too long because altcoins in general will have fantastic prices when they are first launched and over time the price of these coins will decrease in price because investors have moved to coins that are new and still popular in the crypto world.
That's why we can't get profits continuously because every day and every month there will be new projects that are more popular so that the old coins will be left behind.