Andy Newmark Disusses John's Directions

"[John] didn't want to play these [Double Fantasy] songs more than five
or six times once we were on the verge of getting one.  Therefore,
everyone had to play really simple and consistent in order to get a good
take quickly, knowing that John wanted to get it within the hour, not
five hours.  If a player started to stretch out, he would risk blowing
the take.  Everyone had to stay right on their parts."
-- Drummer Andy Newmark, quoted in Ken Sharp's book Starting Over
Lots of studio participants and observers noted the same thing about
Lennon's desire for his sidemen to play simply.
When and why, however, did Lennon begin to require simplicity from his
coworkers?  On Lennon's best Beatles songs -- say, "Rain" or "Come
Together" -- Paul and Ringo were allowed to stretch out.