Just had a long coffee chat with a friend, who has been long time cyclist and local cycling advocate until a few years ago. She's probably 79 but now having problems with shoulder and can't cycle safely far.
She is noticing for friends in her age bracket and older, who now can no longer drive and are trying to use public transit. She felt it was endless unnecessarily long discussions and too much worry how to plan local transit trip planning when some friends don't live far from transit nor do they have to switch buses.
The lesson here is: Integrate use of public transit into your life NOW when you're still mobile, healthy. Learning to use transit when you're disabled /frail is not the time to learn.