I was paying for three cats and two dogs. The amount I paid in the year was more than I spent at the vets, so I just bank the money now and self insure. There's definitely a risk that you'll get something expensive comes up but you'll likely have a nice little stash to contribute towards it. Even if I add up wee Rosie's chemo, none of the other animals needed the vet in that time so we were good.
And since they're all on either raw or biologically appropriate food, I find we need the vets less and less.