Its really depends on the project itself. If the project has potential to be a successful one in the crytoworld maybe you can hold atleast a month or two just to know if the project is suitable for everyone. I suggest that you should read the whitepaper so you can see their goal for the coming months or years. And addition to that, the current situation of the market is not suitable to hold new coin for a long time. Its to risky and the market is to unstable to the extent that its always on a red mark.  Its always your gut feeling or read the trend on what is the best thing to do.