Let the aircraft decide. Get a Piper Cub. If you no longer can climb into it, you no longer can fly it 
Let the aircraft decide. Get an F16. When you are no longer ahead of it, it’s time to go…
But, seriously, at 66 I still enjoy flying and see no reason to give up. I get more medical monitoring than the vast majority of pilots and I am happy with that. But I don’t have a young family, and in general neither of my two sons (27,30) flies with me these days. My new GF loves flying; just starting her on shorter trips.
Currency is the main thing. If one flies less, it really shows.
The longer term issue is the usual one: how to keep it interesting. Many threads on that one
Most pilots who I knew had given up did so due to
Although an AME, now retired, informs me that he failed only about 4% of those who visited him. Many more gave up on medical grounds without an AME visit. One could make two observations: how would he know how many “self-disqualified” (probably obvious from non-returning regulars) and nowadays there is the PMD route which is used by > 50% of UK pilots.
Rob,
Firstly. Good man. Flying at 74. Great.
Keep flying. All you need to do is get the appropriate family members to learn enough how to get it down safely. And then keep them current.
Or get a plane with a BRS.
But whatever you do keep flying. Live !
Indeed; keep flying, and there are downgrade options which will preserve most of the value – especially in the UK where you have the amazing PMD (self declaration medical) option, which can also be used in France if the aircraft is an amateur built Annex 1. This is unmatched across Europe, with the exception of the French UK route but that is FR-only.
I agree with @Dan in so far as the number itself is not important. There are many factors that come into play and ageing does have an impact on them. But each individual is different, as is the flying activity. The more often one flies, the longer the skills are maintained be they mechanical or mental. I have a friend who will turn 84 within the next few weeks. He has lost track of his hours ….. must be somewhere over 30’000, never flew for an airline but did a lot of instruction and has flown all over the world. He keeps a bike in his aircraft and gets around on it after landing. Fit as a fiddle. He recently put his aircraft up for sale but continues to demonstrate for, instruct, and examine glacier flying candidates. There are certainly outliers, but in the end it comes down to the individual and his/her flying history, motivation, and health.
