BPJ
From the experience of my 60 yo aching unfit muscles and weak eyes, I would strongly suggest to look at your body first. Cover any personal weaknesses there before anything else. 
Just as an example from my side. Eyesight is a big problem in my case. So, I have put the following aids : 
- In my glove compartment , a new bi-focal pair of glasses, and a cheap pair of glasses that can serve in emergencies plus I can combine WITH the normal glasses to convert them to reading glasses ( just like a pair of hands-free magnifier lens) 
- Also, in my bag, I have put a vision pouch plus a light pouch. In the latter I have put a headlamp, and a 24/3 LED light that can be fixed with a hook or magnet ) 
The list goes on and on. 
Without proper vision , I am helpless 
And so, survival begins from there. 
I once developed a knee problem, so I put a cane in the trunk just in case. Although, I am ususally fine and the problem is gone, but could return in the worst of times. 
So, please find your own personal weaknesses and address them before anything else. 
Just my 2¢