I needed to resize a gold ring I bought at an antique shop. Birks came back with a repair estimate that was 2x what I paid for the ring and 10x what I ended up paying for the resize somewhere else. It then took two weeks of phone tag to get my ring back from them. I left messages, which Birks did not return. When I came by, they told me I needed to leave more messages because the ring was still at their workshop, and they'd call me. They didn't call me.
Once I got the ring back, I took it somewhere else and got it repaired for a tenth of what Birks quoted. That's right -- Birks has 1000% markup.