I've been reading Mark Lewisohn's superb Beatles biography and while doing a bit of Googling as a sort of accompaniment, came across this priceless image from (I'd say) the mid '70s.
I believe Ringo is wearing an Omega Time Computer; not sure what Keith is sporting on his right wrist there. A Pulsar?
A similar image is also published here and there on the Internet flipped horizontally, so that Ringo has the watch on his right wrist. But he was left-handed, so it's more likely that he'd be holding the glass in his left hand.