It was a confluence of events but the main thing was playing clubs in Germany, basically playing covers for something like 50+ hours a week on and off for two y

It was a confluence of events but the main thing was playing clubs in Germany, basically playing covers for something like 50+ hours a week on and off for two years. And they were playing late at night to drunken crowds, so they could experiment and goof off too. That's how John, Paul, and George developed their impeccable harmonies, tight playing, and a massive repertoire of hits. That's just an absolutely crazy amount of hours to be performing in such a short period of time, and nearly impossible for most musicians to actually get paid for (outside of relentless busking).