How long can an indoor/outdoor female cat live if she is loved and cared for by a loving family of three, one mom, one little sister, and one big sister, plus a three month old female lab puppy, a parakeet, three chickens, and two other cats in a small log house in a twenty one acre forest?
Every cat Anita and I have had in our 29 years of marriage has made it at least 16 years, save one who succumbed to a bad drug reaction at the vet's at age 6 1/2. "Calling Name" (if any) will be in parentheses after the registered name.
Our current 4: (the semi-famous) Miss Teia Honey (Teia) is a little over 12 1/2, Silver Kestrel the Ransacker (Kissie) turned 11 in April, her 1/2 sister Hildiekatt Halfshadow the Harrier (Monkey Baby) will be 10 in November and our current baby-cat, Chesapeake Bandylegs the Hunter (Bearby), will be 9 next month.
Our previous 4: (the sisters we adopted in February 1983) Queen Victoria Grey (Bearkin) made it to 17 1/2 (heart attack), Calamity Jane Grey (Tookie) made it to 21 1/3 (massive stroke), April Dancer (Gremin) made it to 6 1/2 (anaphylactic shock), Cerridwen Blythe (Foofie) made it to 16 5/12 (kidney and liver failure).
My family's cats (before the advent of modern pet nutrition): Lily made it to 12 years, Baby Cat made it to 12 years, Tiger made it to 7 years (unaltered Tom, only one either my wife or I have ever had, if fact, only unaltered cat of either sex my wife or I have ever had), Tuna Cat made it to 16 1/6 years (Tuna was my little buddy, who I had to leave with my parents after I got married, as the military quarters to which my wife and I were moving allowed NO pets. Tuna became my dad's reading buddy, though she was mostly an outdoor kitty).
My Wife's family cats (that I knew) : Sylvester Junior (Junior) made it to 16 1/3 (outlived a kittenhood diagnosis of FeLeuk by 16 years), (these next two kitties were pedigreed Siamese and were full brothers by different litters) Tiger made it to 22 11/12, Fonzie made it to 22 5/12...
So, with care, kitty can be a companion for a very long time.
Us, we get them to the vet at least for the yearly checkup and shots...
Food: Purina or Friskies wet and dry...nothing fancy or scientific.
YMMV