Looking at the past few days we can see that it is very important to hold and sell Altcoins or Bitcoin at the appropriate times. Because Bitcoins fall so quickly and keeping them can sometimes leave you with no money.
Personally, i won't advise anyone to always look back into the past becasue it sometimes painful seeing the current market price. Those who sold early somehow sold in profit which made them not to look into the past. Early this year, i sold some of my Bitcoin which i hold from 2018 and this sold made me some good profit before the market exploded few months ago, but i sold in profit was my consolation.