If it is bitcoin you have in your portfolio, I will say you have made the right decision to hold it for as long as possible because bitcoin investment is suitable for the long term, and you will surely reap from your bitcoin investment if you are all in for the long term, but if you are talking about altcoin, I will advise you to sell it whenever you are in profit because if you want to hold it for the long term, other investors will take profit from that same altcoin you are holding and use you as an exit liquidity, which could expose you to losing your money.