A dumper takes what they have invested, see a gain ans sells for profit or very small loss. In your case if at any time your investment was worth more than half then sell half and keep the rest for what the purpose of the coin was. i.e. staking.

A loss or bad investment is when you could of sold for a little gain or little loss. these feel better a month later because 1. you can take your gain and more more for less or 2. your loss was smaller instead of bigger when or if a coin fails. Yes keep a little to stake if you want your wallet opened all the time.