And here's a story about waiting too long. My son and DIL have an adorable long-haired, dappled, miniature dachshund. Adorable, that is, until she sees someone she doesn't know well. Even with people she does know, she would get incredibly cranky. She's one of only two dogs that have bitten me since I became an alleged adult, and she likes me.
For years, she's had really bad breath. Not normal dog breath, but breath like something crawled in her mouth and died. I've been urging them for years to get her teeth checked. I'm astounded that their regular vet didn't say something, or maybe she did and they declined. About six months ago, they finally took her in for a dental and they ended up extracting 11 teeth. Everybody said, "Oh, that poor baby!" But, no, for the very first time in many years, she feels good. She went from being a foul-tempered, unpredictable terror to a completely pleasant little girl. She still has plenty of teeth and can eat just fine, and could bite you if she wanted, but she no longer wants to bite anyone.
Now, of course, they feel terrible that they didn't take care of this sooner.