How do we know when to quit

I have stopped half way up the Napton lock  flight and this is my lovely, if somewhat damp view from the loo. I stopped because I judged that it had become too windy for me to safely continue.

But that is not the reason for the title of this post. On the way up the flight I met an elderly man coming down. He was obviously struggling. He took ages to open the top gate and by the time I got tied up and went up to him he had only just got his boat into the lock and was fiddling about with the longest rope I have ever seen on a boat! As I approached he tripped over the rope and only just remained upright. I told him that, if he wanted to, he could get back on board and I'd work the lock for him. I opened one paddle but he was so busy explaining how difficult he was finding everything and how he had recently cilled his boat! that when he went to get on board he had to use the ladder. That was terrifying to watch and I was busy making a plan in my head should he fall!

Eventually I got his boat out of the lock, but was so concerned that I asked the boat behind me to see him through the next lock and in return I would set my lock for them once I had got through. As it was, another boat came towards me as I was ready to leave. The lady asked me if I had met the elderly man. I told her of my encounter. She told me that they had followed him down the flight so far and very nearly had to fish him out of the lock as he had slipped on the stone surround and had fallen over!

It made me wonder how can you tell when it is time to hang up your windlass? Do you stop when a) you become a danger to yourself or others? b) when you start to terrify yourself or c) when you are so slow that the whole lock flight grinds to a halt!

I don't think that b) or c) are good enough reasons to quit as I regularly terrify myself but I still love it and speed should not be a factor when boating. But a) is a harder one. If this man had injured himself (or worse) today it would not just have ruined his day, but would have disrupted everyone else on the flight. The emergency services would have had to come and looking at where we were, it almost certainly would have involved the air ambulance.

But then how can you tell when to quit? Not just boating but anything you really love to do? I don't know the answer to that and I may need to know one day. At present I can't imagine not cruising my boat whatever age I get to. And perhaps the chap I met today is the same. Does anyone have the right to stop him?

Answers on a postcard please!