Pet Lovers of the Couch

I've inherited an elderly dog. I've never seen an animal with a mouth as bad as this one. It's just so horrible. The teeth she does have are BLACK. Tartar, decay, death. The smell is indescribable. It's just awful. I can't imagine how this couldn't be incredibly painful and causing systemic bad health.

I've a consultation at the vet on Monday. They're going to quote a price that will make me cry.

Is it worth going to different vets to get quotes? Do prices actually differ from vet to vet? Is there a way to negotiate prices - or to do only that which is absolutely necessary? I would love to get some advice from folks who have experience with this sort of thing.