It is not set in stone, but first - regardless of your risk profile and/or appetite - you want to make sure that you hold your tokens in wallets of which you control the private keys. This means to keep your tokens off the exchanges and preferably use hardware wallets. In terms of price increases, it depends on your risk profile (appetite), but it is not a bad idea to always make sure that you get your initial purchase back soonest and to always make sure that you hold at least some tokens for potential medium to long-term growth. A lot depends on the project as well. You should make a list of the reasons why you got involved in a project. If those reasons changed for the negative, it should give you a pretty good idea of what percentage you should hodl and what you should sell. You might also want to have a look at technical analysis or subscribe to a service that tells you when to get in and when to sell. At the end of the day there is a lot to consider, but getting involved in quality projects and not beyond your financial means are normally the safest bets. It is then when one usually feels more comfortable hodling.