I think that greed can destroy your whole profit if you leave the coin by keep in mind that it will enhance more in value then its your big mistake i will suggest that if you have profit and gain then you should not keep holding because the condition of market is undetectable. No one knows what will happen with the value so do not make decision with greed in mind. You can surely sell and take some other coin for your profit.
If you arent that type who do likes to wait then making out short term sells and buys would be you line but this isnt for everybody because this is really a hard kind of trading if you do ask me.
secure profits if you do need too but if you are seeing it on an altcoin then its not bad to secure it out but if you do believe on projects potential then its your choice to hold for longer.
For my part then i would secure profits and those profits would be reinvest and would diversify those in other coins which would give out more chance possible profits.