I was in the mid 60's and a buddy said "Hey, try a faster cadence" I did, now about 80rmp and I like it a lot more.
I downloaded a bunch of 80-85bpm songs and played them to get the cadence ingrained in my head.
My knees like it better too.
50yrs old 6'ft, 200lbs.
20-60 mile rides, 18mph avg.
Jeff