if the price rises to $1000, I would sell most. then still hold partly because of my fear of regret when bitcoin prices could rise further to $1500 in a short time. but if it does not increase to $1500 and fell back, I was lucky to have sold part when the price $1000
that's why it is a good idea to have several wallets containing the coins that you have for investment purposes. one wallet for the coins that you want to hold for a few years, another wallet with coins that you plan to sell when the price reaches a certain level, and so on. i do that too, and so far it works out pretty well for me.