Altcoins for long term holding is ok as long as you can monitor their prices all the time specially if you're full time in crypto. Its good to have a lot of altcoins in your portfolio but you also need to check every coin's prices to know which one will be needed to sell to to hold. During corrections or down trend, prices are very disappointing because all of them are starting to fall down. Sell them if you need to avoid bigger money loss .