Sure, to take profit is something recommended for everyone, no matter how long-term their investment is. Sometimes, however, taking profit means receiving dividends, interest, or other forms of benefits, and not selling "the principal" for a very long time, if the project you are invested in is doing well. Sometimes a balanced approach is better, but if you are a major investor in such a project, the option of selling is not always on the table (or not for a big share), at least not without hurting the project.