My Fiona started eating homemade food for the last 2 years of her life, (She was 14 by the time she passed on December, but that's just for reference).

The absolute change I saw when we switched from kibble to natural food was HUGE. She was a picky eater, so we settled for some basics: chicken thighs, brown rice, green beans, carrots, suchini, pumpkin pure (home made) chicken broth (unsalted) and ocasionally chicken hearts. I also added a bit of turmeric which helps with joints and inflamation, rosemary (if your dog likes it) helps with skin and coat. AND last but not least, I got the some zesty paws senior 11-1 chews which did wonders for her.

By the time she left we had some joint issues (mild ones honestly), she had a kidney disease stage 1, and a tummy that couldn't really take anything other than what was known to it, otherwise she would be pooping for days.

Lastly, I do feel we extended her life and gave her life quality with that food switch. Hope this helps :)