Our old vet didn't offer on-call service. They closed for the night, and that was that. So the Emergency Vet is there just in case. Why they have to charge astronomical prices is beyond me, though, I guess they don't get enough business to pay the bills, so the patients that they DO get have to pay a bundle. Just like the human ER
We also now have a new vet that has 4 vets in the practice and one is always on call and will meet you at the clinic, if necessary. I haven't had any need for after hours care, thank God, but it's nice to know that they are there. They will also bring home a critical patient and don't believe in leaving an animal unattended if they just had surgery