I get a newsletter from Petplan monthly called "Fetch." It always has an example of a claim that they've paid. I decided to visit their Pinterest page and found they had pinned a bunch of examples of claims they have paid.
Looking at these claims is insightful. It gives examples of real life events that happened to pets that resulted in a significant expense. It emphasizes that you never know what will happen or when it will happen as well as the potential expense involved in diagnosing and treating some of these injuries and illnesses. This can help you decide if you need to purchase pet insurance, and if so, how much coverage you should get.
I always recommend getting the highest annual and/or per-incident maximum you can afford. You can see from these claims that even with a normal surgery, complications can develop that are more expensive to treat than the surgery itself.