Before making the decision to sell, think about why your coin has went down.

Your coin is down to a point where you're afraid about your investment and want to sell. Or you're uncertain about what to do. Should you sell or hold in case it climbs back up?

To find an answer to that, look at the reason why your coin is down. The market is volatile and there are millions of reasons for the coins to go down so find out first if your sell is justified.

Is it because the market has crashed? Then that would mean that the whole market is down, not only your coin, and if you invested in it in the first place because you believed in it, it doesn't make much sense to sell because your coin hasn't failed but the whole market has crashed, and if your coin is one that you have high hopes for, if it's a reliable coin, it will climb back up and you shouldn't sell.

Or it could be that the coin has been doing very good over the last months and now the price is down, but again you must stop to see if it's manipulation by the whales and if you think that it is, and that the coin hasn't failed, then again holding is the best option.

But on the other hand, if your coin has went up 10x in just a matter of days, then you might want to sell it because a coin that can easily go up 10x in such a short time can also go down 10x and it's too risky, even if you see investing as gambling. This is the case with 90% of the market, low cap obscure coins.

This has proved to be the case even with Bitcoin, the hype make it go up all the way up to 70k and it crashed down to 40k in a matter of weeks, because that price had been reached by hype.

Or you know, your coin just went to 0 and you've realized that you just got Rugpulled, not much to do in this case so don't think about it.