Market is down at present and i think invest as much as you can as after correction phase prices would surely surge and high profit is expected on return.Holding currently is another good planning to earn a considerable return as per your planning.If you sell your investment due to low prices you would not be able to receive much profit.To me currently both Investing and holding strategy are inevitable...
Dunno, investing is really may really worth it, just find a good ICO to invest and you're done!
Seems like you slipped of the topic here. He is asking about the coins which he is holding and whether he should buy more altcoins and also keep on holding the ones he has. As far as I can see, he hasnt mentioned anything about investing in ICOs. Also, most of the ICOs nowadays are scam and ponzi schemes and has no real world application or utility. Better to invest altcoins and bitcoins rather than ICOs. Take advantage of the dips, ICOs can be bought anytime as it has nothing to do with market crashes.