I'm 75...in 2017 I had a lung infection, lost a son to suicide, was hospitalized for an aortic abdominal aneurism, survived a hurricane, and had cancer surgery for a node in my right lung. I haven't built a model in over two years.
With that in mind, I think you also must take into consideration the lessening of skills, eyesight, hand/eye coordination as you grow older, as well as other factors such as emphysema and Parkinson's Disease.
All of those grand and glorious financial plans fall flat if you're not physically or emotionally capable of performing the tasks! I have no credit card debt or car payments...just the mortgage and I can handle that. Building models is another thing...I now have to set aside time for working on models...not exactly how I had anticipated my retirement.
Take care of your health first...the financial aspects mean nothing if you can't enjoy them.