Given that the market is now struggling due to the natural market volatility, holding is essential. i am personally planning to sell only those alts that are having low market volume and hold into those that are promising. It is surely scary to see that the majority of the market is on red marks, but since dumps are not permanent, holding won't result to profit loss.
I agree that the market is struggling but yesterday and now the market is getting better specially bitcoin. Its going to recover very soon. But i am not sure the other since when bitcoin was increasing price yesterday then the other coin is dropping. Its not normal but maybe bitcoin is stronger than ever.