Should we hold on to altcoins which we have invested and see the price dropping every moment or it will be better to sell them and buy it again when the value pumps ? I have already lost a good margin of profit with the ripple I don't want to make the same mistake with the Lumens which I Hold so should I hold on or sell out ?
Hold or sell all depends on you and on the coins you have. It is better if you do the first analysis of the coins you have, whether it has the potential to continue to grow or not. If you think the coin will actually continue to decline, it is better to sell it even though you suffered losses but not big losses and re-invest your money into other coins.