It's not about life expectancy it's about your body not breaking apart. She's freaking logging at 70+, look at how quickly she cuts the fire wood with a bow saw try it it's not easy especially in the cold when the wood is frozen solid and the saw gets stuck every time you lose the stroke rhythm. I've done several "treks" under less extreme conditions with modern equipment and it's bloody hard even basic camp management (Find dry fallen wood, cut it into fire wood drag it to the camp site, go get water from the stream drag it to the camp site (uphill always ;), fish/hunt, prepair your food that's easily 6-8 hours a day even with help, she's doing that and more everyday...) takes most of your day and it's exhausting and this was as a healthy male in his mid 20's, she's full on homesteading pretty much alone in extreme conditions in her 70's while taking care of a 1 legged man her age if that isn't impressive please let me know what is...