there are about 1700 active altcoins and they all have potential of getting pumped and this MARKET is seeing some pump 24/7 of 365 days of the year. it is your task to find them, invest in them during their pumps and also get out by dumping them before it is too late.
waiting for some sort of miracle while holding some altcoin because it is higher in some ranking is just going to lead to a lot of losses.
Yes you are right. Do not hold the altcoins too long, if there is a chance of selling them well, you do not need to be greedy, because sometimes this can lead to really big losses. you need to sell and buy coins on time to get a good profit.