Odd that two failed at the same time. I would think failed breakers were the least likely cause of the problem unless there is evidence of damage. Before I replaced them I would check their continuity to see if they really are bad, and I would look for loose/broken wires and connections starting with ground wires. I recently had my inside courtesy lights fail, and after a couple of hours of removing panels and tracing wires I found a place in the overhead where the wire had been rubbing against something and chafed through.
-charlie