These people have one thing in common...
Hugh Downs
Carol Channing
Henry Kissinger
George Bush
Jimmy Carter
Eva Marie Saint
Charles Van Doren
Alan Greenspan
Hugh Hefner
They're all over 90, and to one degree or another, still active and involved.
That speaks well for activity.
On the other hand, we all know folks who stayed active, involved, and flexible... but died young.
It seems to me, a matter of age and health, and that means individual differences. For the years before retirement, life was very active. Four kids, a job that ranged from 50 to 70 hours a week, 22 lock stock and barrel moves, and 25 years of Scouting, Little League and Church Youth Groups... community involvement. After retirement, for the first 20 years, pretty much the same activity level in different venues. Anything but routine. Travel, Camping, three homes...
At age 75, changes... memory problems... more need to concentrate... less able to multi task. Gradual slowing down. Taking longer to do what used to be quick and easy. Dropping some of the "as usual", fewer contacts with relatives and old friends, driving more of a chore than a pleasure, and easier to eat at home than going to restaurants.
So that's the activity part. Before getting into routine, a simple observation:
Time goes by too fast. Getting up a 5AM, and suddenly it's noon... Dinner at 5, and about an hour and a half later, it's 9 o'clock. Creativity is wonderful, and it's really fun... but it also takes longer than it used to.
That's where routine comes in. While I like to think of it as "efficiency" that's not true. Without building "routines" ... "normal" becomes confusion and everything becomes more time consuming and less pleasant. Now, we actually... for the first time, use the refrigerator calendar to plan our activities. Spur of the moment stuff, not so much.
But, before this becomes much ado about nothing... it was not what we envisioned. Likewise, as we become friendlier with people in our CCRC, it's apparent that we're not alone. Sure... many of the 80 and 90 year olds are still active... going on bus tours, attending family functions or going out to eat, but in the off hours, are more likely to be reading or watching TV. Yeah, routine.
So while we look up to those are still in the social strata, and in their 90's... my guess is that the expectations that we have at age 60 don't extend into the reality of the 24 hour day when we grow older.
So... YMMV, and maybe your 95 year old grandmother is still running the local 5K... but for us, the slowdown is in process, and we're not into avoiding 'too much routine', but more going with the flow.
Another wordy bit of thinking out loud.