Most people buy high, HODL, then sell low.
When is the best time to buy bitcoin? It really depends on you ,for me if I have enough condition, I will get bitcoin. You particularly spend much of your time doing research, following the updated information to know the news of bitcoin. If you dont have more capital ,youd better choose the time that bitcoins price goes down to buy, it will be much more convenient for you. Moreover, you have to be careful to avoid the scammers. If you want to do bitcoin for long time, you must learn and read a lot to have knowlegde and analyze market easily.