I have heard this from others as well. Most of the times the experts say that buy low and sell high and use the profit to buy more at lower prices.
This indicates that we should never miss an opportunity to buy bitcoin at cheaper price as it is bound to bounce back to a higher price.
Lol. It's quite easy to say this. We don't even need experts to tell us the obvious thing - "buy when low, sell when high". It is easier said than done to be honest. You never know what price is actually the lowest or what price is the highest. If you believe that the price of bitcoin will go up in the long run, then buy whenever you want. Set a goal and when you reach that profit goal, sell your coins.