I don't see the point in selling if you're 80-90% down on an investment. I understand if it was a big position size that people need to jump ship, but with smaller position sizing selling in order to get back 10-20% doesn't make much sense to me. 10-20% is the minimum amount you want to be gaining in trading or investment, not recovering.
A quick analogy for anyone interested, if you bought something at $5, and it goes down to $0.5, yes that's a 90% loss (in value), but if you still believe this coin can go up 100x, then you can still make 10x your investment in the long-term (instead of losing 90%). Likewise if you think it can do 10x, you might be able to get out break-even.
$5 - buy level 10x
$4 - 20% down x8
$3 - 40% down x6
$2.5 - 50% down x5
$2 - 60% down x4
$1 - 80% down x2
$0.5 - 90% down
(xX reflects increase from low to buy level)
Also as relevant is that if the coin goes up just 5x (yes, "just" because a 4-5x gain is common enough in a few weeks or months), then you will only be 50% down on your investment. If you still believe in this project, by buying the same amount again, you will drop your losses to 20-25% under the price, which is basically nothing in the broader picture. Alternatively, if you want to then get back half your money it's a lot better than 10-20%, about 2.5-5x better
A weird example I know, kind of obvious maybe but a lot of traders don't look at things this way. Some of the best gains I ever made were after projects lost 80-90% of their value, baring in mind that all the biggest coins and projects atm all lost 80-90% at one time or another. These things are actually natural.