I save my coins for as long as possible. I sell some of my coins if I see that I can make some money but I never sell all my coins at once. That is just not a smart thing to do. The price can go up at any time when you at least expect it.
yes all depends on the coin. if it looks to have a good project and dev are always updated on the coin. I also dare to hold such coins as long as possible. because usually there is always a high rise.