Quoted in The Beatles Anthology (John) ↑

It got less group-like

With The Beatles it got less group-like. We stopped touring and we’d only get together for recordings, so therefore the recording session was the thing we almost rehearsed in as well. So all the playing was in the recording session. Sometimes it would be a drag — it’s like an athlete: you really have to keep playing all the time to keep your hand in. And we’d be off for months and we’d suddenly come into the studio and be expected to be spot on again.

John Lennon, as quoted in The Beatles Anthology