we keep the coins at least 5 years , but its too long imagination. you can proof it. 2018 early NEM coin was top 6 Marketcap now 56. so keeping its useless. we have to updated everytime and get the action the correct time and exit.
Or just search the good coins to begin with like Bitcoin and Ethereum.
5 years are a long damn ass time to hold especially in this cryptocurrency world. You stated in 2018 so everything was just a hype back then and if the project is not being known by the community then it's just pointless.
Also do make sure you have another income source to back up those investment in case you need it urgently, because you don't know what you expect in 5 years.