One of Dr. Mona Rosenberg's clients was a loyal pet insurance customer—the client renewed her plan year after year. By the time this client came to see Dr. Rosenberg for cancer treatments for her dog, it was time to renew the plan for the year. But the pet insurance company denied renewal of the client's plan—and now considered the dog's cancer a preexisting condition, even though the client had been a customer for years. "If you've got heart disease when you get insurance, they're not going to cover you for developing heart disease because it's considered preexisting, I understand that," Dr. Rosenberg says. "But if you have a policy in place and you develop a new health problem and you start paying your deductible again, it seems ludicrous to me that the insurance company can call that a preexisting condition." The dog's chemotherapy became on out-of-pocket expense—and the client later canceled her pet insurance altogether. Dr. Rosenberg says for future pets, the client still feels like it's a good idea to have pet insurance, but she's going to look into other companies. "And now that client has the tools to ask more questions as she's researching other plans," Dr. Rosenberg says.