If I purchase a biological supercomputer, how long does it take for normal cell death to render it ineffective? Humans have a planned obsolescence of around 80

If I purchase a biological supercomputer, how long does it take for normal cell death to render it ineffective? Humans have a planned obsolescence of around 80 years but a (large) dog only lives for about 10 years. I guess in some ways this is no different from electronics manufacturers gluing their computers/tablets/phones together (or building them with non-replaceable batteries) but I'm opposed to that trend as well.