Never hold any altcoin for long time. It is possible that the coin will be lost forever from all the market, there will be no volume at all etc etc. Because you don’t know what's going to happen within these long time. There are a lot of examples, many coins were in huge boom in 2018 altseason but they don't exist now. Even if they exist, they have no volume.
Yes, it actually happened to me. Some of my coin merged with other project that is why it is untrackable now in the market. If I know this will happen, I should have exchange it.