I think it depend on the project itself, if the project you are hodling is not showing any potentials, it is very wise to sell while you can because not all alts deserve to be hold for a long period of time, you have to see potentials or activeness on the part of the team to hodl.
I think that the project has a lot to do with that. The point of trading is making money, the project should trade it's crowdsale funds.