It is more precisely “sell your Bitcoin at the right time” because if someone buys Bitcoin usually the goal is to get profit, and when they want to achieve maximum profit then they need to sell their Bitcoin according to the goals they have previously set, for example like 4-5 years in the future. Because how can they get the profit they want if they never sell their Bitcoin? that's why they need to sell at the right time to get the profit as they expected before.