My mom quit when she was hit by a car at 86 and found she couldn't recover enough strength to begin riding again. (Not her first accident at advanced age but she had been able to regain strength aad continue before.)
Her house (the house I grew up in and rode from many times, including my first year as a car-less bike racer) has a 1/4 mile dirt driveway that while well built and maintained, has always demanded a baseline of strength and ability just to navigate.
So I've got a long ways to go. 2 more decades. And I don't have the excuse of a dirt driveway.
Ben