It's all about managing expectations. Usually you underpromise and overdeliver, customer happy. Also in this day people expect an email or whatever with updates, quickly. It would be good if Don had some sort of management system where people can see their status on web or something, like by serial number or whatever. Or hire an admin person for email only and raise prices by 20%!
My M6 took close to one year to fix (loose RF prism and broken meter, nothing too major, but that was just my assessment). First I emailed/called every three months, then in the end once a month. When I got a response it was courteous and to the point. In the very end I realised he was waiting for a used spare part to come up to save buying it expensively new (meter board) - much appreciated, but of course while waiting I did not know that. Managing expectations.
On the plus side, when I finally received the camera back it was like having bought a "new" used camera, without spending too much money. And I did not have to bake a 1st anniversary cake 🙂
I think for bodies I would only deal with the premier league and buy a second body in the meantime 😉. Lenses and conversions can often be done elsewhere.