This article is from the rec.pets.dogs: Assorted Topics, posted to rec.pets.dogs newsgroup. Maintained by Cindy Tittle Moore with numerous contributions by others.
Pet insurance plans are typically accident policies, although some also cover routine medical expenses such as worming and shots (or even grooming) -- the latter are generally a better deal.
Between the deductibles and allowances, you may not get very much back on an actual claim. In several years of rec.pets.dogs, no reader has come back with a favorable story on claim processing.