Good question…I have been holding a lot of Altcoin, and I got burned badly. One might say why that is. Well here is what I think. A great deal of altcoins that I was holding were not in the top 100 in the market-cap, thus when all the coins got hit mine got hit worse, by losing tenfold the value of the coin.
Now I try to hold coins that are quite solid and are on exchanges with a lot of volume.