I suggest the proper definition of the word 'safe' is - 'a situation or condition where the risks are minimised to a level which is tolerable to the stakeholders'.
I am in a similar situation. I am 80 and my wife does not want me to race again. If I choose to go around her, I would probably be being 'unsafe'. What she fails to realise, is I ride a motorcycle better than I could ever drive a car. I have had all my crashes already. The last time I raced, I raced better than I ever did.
Alan, like the OP I am 68. I have entered a race in Belgium in August. I ride an old AJS single on the road and I kickstart it.
We should all reassess safety and practicality every time we ride, I was deciding that the AJS was getting too much work to start and put on the stand, then I changed the centre stand and the carb! It is practical again, but I am probably doing a bit more exercise too.
Today isn't the same as yesterday, and it changes daily, not 'decadely'.
'The last time I raced I was fine' is OK when that last time was last week, but when it is 10 years ago we are probably dreaming!
For me, my last ride on the AJS was last week, but my last race is more than 2 years ago. The last time I was on track was last September. I was fairly comfortable and safe over that weekend, but it wasn't a race on a 5km road circuit, so I will have to take the race meeting as it comes.
The last time could always be the last time, I want that to be by choice, it doesn't have to go horribly wrong, we just have to assess how it did go and decide, during or immediately after the event, is it time to quit?
One day it will be over because 'it ain't fun no more!' There are a number of reasons 'it ain't fun'. And that includes it not being fun for others to be around us! You have to understand how far you can push that, too. I can't imagine doing a race meeting without my wife, who was at the first one in '75, both being there, and onside.
It is my itch, and I have to scratch it too!