My Dad quit at 70 when he had a November accident in the Westport River in late October. His nasty plastic Sport Yak III skittered out from under him and he was in the drink. He couldn't get aboard it or the 21 footer and there was no one else out on the river. So he kicked the dinghy to shore and walked to Tripp's Boatyard. He was alone. The yard folks helped him get warmed up. I'm more fit at a similar age and will try to avoid his exact mistakes. Hopefully I'll know when its time to call it quits.
We have a great boat which makes sailing easy enough in most conditions. I'm pretty much done with multiple overnight passages in gale force conditions (never my thing!). I don't bounce back so well from sleep deprivation and hard sailing conditions. So, a bit of pacing and prudent choice of conditions and it is still loads of fun. I'm fortunate that Susie is a sailor through and through and can manage all aspect of the boat. For brute force she must lean on me to horse in the genoa. I count myself lucky.
I'll always remember my high school PE teacher/wrestling coach intoning: "You wanna be tough? You wanna be crusher? Ya gotta worrrrrrk! If you don't worrrkkkkk, ya gonna get hurt!" He's right. I need to get on the bike more and keep it all working. The knees have been very good to me, partly because of years of bike commuting. I've logged fewer than 50 miles so far this year. Baadddd! I'm fortunate that so far I don't seem to have any degenerative time bombs going off.