One of the worst things about losing a pet to illness (esp. in the Internet and social media era)? The frequency with which information about what your pet died of begin to plate of shrimp you.
For example: when it come to an illness like kidney disease, how we feed our dogs means that, when the disease has progressed to the point of causing nausea, we've no meaningful way to entice them to eat. Our dogs' daily diet consists heavily of what kibble-fed dogs would probably consist of "treats" (our dogs get real meat, veggies, etc. - so, those aren't really "treats" to them).
Also turns out that dogs quickly associate the nauseated feeling with whatever foods they last ate before becoming sick to their stomachs. With a diet that doesn't leave many things as treats, there's not a broad spectrum of foods with which to entice them to eat. And, because they quickly associate the nauseated feeling with the "treat" foods, that limited-spectrum of "treat" foods is more-quickly burned through than dogs that get the same, manufactured dog food their entire, pre-illness lives.
One of the other suck things about kidney disease is, because your pets can't tell you "I feel sick": you don't usually see symptoms until they're well down the disease's terminal-trajectory; the early symptoms frequently display in a way that seems like behavioral issues rather than obvious signs of illness.
In the case of our cats - particularly our female cat - this manifested as urinating outside of her litterbox. Earlier in her life, eliminating outside of the litter box was behavioral. Things that had prompted it in the past had been: changes to litter-brand; annual vet-trips; us going away for family holidays (Bella got carsick and hated being taken on trips); us going away for work trips; us going away for vacation.
While we always had pet-care, Bella was generally upset for a few days after we got home. This would frequently prompte her to pee on Donna's things (presumably, she blamed Donna for our infrequent absences).
The litter-brand changes weren't our choice. For whatever reason, litter-makers always seem to see the need to "improve" things. And, to "encourage" people to switch to improved products, they'd discontinue the ones our cats liked. This happened a couple times with their litter and at least twice with their food.
As to the vet-trips: it's not like we could, in good conscience, choose to not get them annual exams and shots. I realize plenty of people do skip all that, but I've always tried my best to keep ahead of our pets' health needs. Thus, we were conscientious about veterinary care, diet and the like.
With the exception of the cats - who lived a year and a couple days beyond what was expected for their breed - that conscientiousness seems to have been in vain. We lost the first dog we adopted to cancer after only a bit over seven years ownership. We lost the second dog we adopted to (a different type of) cancer after a little less than seven years of ownership. We just lost our third adopted-dog to kidney disease after just a bit more than six years of ownership. Really hoping the first three dogs were an aberration. It would be nice to see one of our dogs actually live to a ripe old age.