We all invest into cryptocurrencies in order to gain profits in the future so when a coin of mine increases in value after a while i mostly sell part of it and keep holding but if it's a project i really don't believe in looking at the vision of the team i just sell everything. It's better to sell it all off at some poin in time than keep holding because some coins may not rise ever gain due to some poor strategies being put in place by the team of the project.