Answer the question: there is nothing best or worst about the time when the bollinger band is used, depending on the currency pair you operate. For example, the euro/dollar is different from the pound/yen.
I personally recommend 30min or1h.
Experts think (of course I'm not): the best indicator is no indicator, but the moving average and K line are almost the most invincible indicators!
So many soliciting people. . . . interesting