It depends on the coin, if you want to sell it or invest. Fro the current situation right now of the market most of the coin are on its low value but if you know that the coin has a good future you can invest on it or hold it because the time will come it will rise again
That is true about selling and investing coins ,these activities are really good move ,if you are carefully taking care of your investment, then you will have the analysis and weigh if this could be a good move for your coins , if you think you can profit for your selling then go , but if not ,you could also try investing more for the next future market, it really depends on the current situations of the market.