There is not a stock answer for this, it depends on the coin, when I got my bitcoin cash airdrop, I was tempted to sell but since my bitcoin was not in an exchange it was really hard to move that bitcoin cash and many exchanges were not accepting deposits, so I decided to wait, to this moment I still have not sold after all, I do not lose anything by waiting, if bitcoin cash drops to zero then who cares I got that for free, but if it goes up in value then I make easy profits.