Well, I thought about this a lot over the years, I have been riding 42+ yrs. I am 56 yrs old. My last serious crash (yes there will probably be more as I will continue at the track) was in 2008. Surgery, 8 cracked ribs, lots of time to consider the consequence vs. reward of riding.
I remember in 1999 I crashed on a straight piece of road in town when I zipped my jacket and while sitting up the thing got into a tank slapper. As I hit the ground and while I rode in the ambulance I swore to myself that I was done. A little healing of the large amount of road rash from that one and I bought a new ZRX 1100 3 weeks later. I couldn't hardly ride it due to the pain, but I got her home, she sat 3 weeks and then I started back.
My daughter rode on the back with me for many years, then when she turned 15 I bought her a DR200E and she loved it. I made her do braking drills all the time and she thought it was dumb...until she had to panic stop when we were riding in town, she locked the front, let go, locked it again, let go and then modulated to a safe stop! What a relief that was for me. She said she didn't even know she did that! I said, "Braking drills work." She never argued again.
Now she is married pregnant with a second grandchild due in December. She doesn't have a bike and only rarely will go for a ride with me. She still had her Taichi leathers and other gear. But she felt the babies are more important than riding. I get that and respect it.
I quit riding for a year once when I was too broke to pay for the bike and dumped it at a loss. That was a bad year.
So now, I have 1 bike (one on the way as well) and I love it. I think about bikes most of the time, I have the tools/skills/location to do anything I need to the things. I enjoy wrenching on them almost more than riding them, so when I can't get on the dang things anymore, I can still fix them.
Motorcycling is fellowship as well, I have met so many amazing, strange, and just downright great folks through riding, that I cannot see a downside. Like any activity, a certain amount of preparation is required to maintain ones skills at a good level. There is a financial component as well, as I am older and financially stable that doesn't limit me like it used to.
So, I guess, I will stop riding when I can't do it or don't enjoy it anymore. I cannot imagine the situation, but it will come as I age. Just another milestone in a fabulous life I was given by God to live. I am one lucky son of a gun. And, I am a motorcyclist for all of my life, I cannot ask for more. Thank God I had the chance.
Fathers Day 2006 Father and Daughter on track, a great day it was.