If you are in bad need and you are left with no other resources but your altcoins, you might be selling them even with a loss for lack of choice. Or perhaps if you are in an emergency situation and there is no one you can borrow money from, you might also be forced to sell your precious altcoins even if their prices are at the bottom. But you will certainly exhaust all means before resorting to this decision.
You are right. I have been in such difficult times, so I have been forced to cut losses and sell most of the altcoins at low prices to make ends meet. If there are other options, of course, I would prefer to hold the altcoin.
In other cases, for example, a token from a bounty, I choose to hold it for a while analyzing the market, if possible then I will wait until the price goes up, at least until it approaches the price of ico or ieo.