I’ve worked on several fleets of cargo aircraft that are mostly comprised of PAX to cargo conversions or dedicated freighters. When they exceed their airframe hours for passenger service, they go to cargo to live out the rest of their lives. I’ve worked on multiple fleets that were built in the 70’s. B767-200’s, A300’s, and DC-10’s. The DC(MD)-10’s on my current fleet are all retired now due to economic reasons, but the airframes are still absolutely solid. The A300’s are still flying but are steadily being retired due to Airbus not approving major repairs for issues related to the age of the aircraft. All of the A310’s at my company have already been retired due to Airbus dropping aging fleet support. The B767-200’s will keep flying for a long time because Boeing has a very extensive aging fleet program. The only limit for the B767’s longevity is the owner’s wallet. With that being the case, the retired A300’s and MD-10’s at my company are being replaced with factory-new B767-300’s and B777-300’s.
Also, the B757’s I’ve worked on will last just as long as the 767’s. The oldest ones I worked on had over 150,000 flight hours and were factory freighters. The company that owned them finally retired them at 200,000 flight hours. They were still airworthy, but they were becoming pretty expensive to maintain and the owner replaced them with slightly newer but less used 757-200F’s and 767-300’s. The 767’s were freshly retired from PAX service (got the IAI P2F conversion), and the 757’s were from another freighter line.
I don’t have any links. I’m actively working in the industry on the maintenance side of widebody aircraft, currently for a company that owns over 400 aircraft. I’ve worked on several fleets and airframes beforehand for a MRO doing similar work.
I’ve played with randoms many times. Most people have been good to play with. I highly recommend it.