It's fun to pretend they're switching parts at the time the song is recorded, Raxo. Just to imagine plugging in those different voices.
Kaleidoscope_Eyes, you can hear John Lennon sing "Honey Don't" instead of Ringo on the
Live at the BBC collection. I think John could have sung "Everybody's trying to be my baby" at one point-- he mentioned in one of his interviews that George never used to sing. Then again, George probably originally brought the song, as he loved Carl Perkins. They probably developed George as a singer out of self-defense in Hamburg; all those long hours would have shredded their voices, so they traded off to share the load.