Not just any cryptocurrency but bitcoin to be specific, and let not be deceived thay by hodling any crypto like we are to hodl bitcoin that we can be sure to make profit, we could be holding a bag of worth nothing.

I think for altcoins just like investing in bitcoin knowledge here does  applies for both but we shouldn't be courageous to the extent that we have to invest in with amount we cant afford to lose especially for altcoins. As for bitcoin you could be patient for a circle or two and be sure of raking in some profits but altcoins has more tendency of dumping than it gives profit in the  long. For altcoins always take profits where opportunity is open and don't be greedy.