I have sold those which were in the profit for me and kept the rest one until I find the right exit point for them. Altcoin holding could be painful as it takes lot fo time for them to get developed and then circulate in the market with proper marketing. This then gets popular slowly slowly and then people will start using it over the course of time. Then you can see some prices spikes and exit points for you to leave the market and grab the profits as well. So you see if you have to reach at the end then you will need to wait and wait for long time! Im holding some of the coins for now this includes, ADA, IOTA, JNT, IPL, ETH.