But when that end does finally come, Hayes can take comfort in knowing she taught an old dog the most important new trick of all - to be loved is to live.
"Jay-Z taught me to cherish senior animals, who need love and comfort the most in the final years of their lives. Just like people," Hayes writes in the practice letter for the dog's funeral.
"She taught me to appreciate the little things like basking in a sunbeam together or sleeping in late, cuddling on a Saturday morning," she notes.
"I will never, ever forget her sweet face, her howls at the firetruck, her licks on my arm, or her little trademark tongue, as long as I live."