Another example is the B-52 where the oldest frames are expected to see a century of flight.
Yep, and the B-52 is an interesting example, because its service life has proven far longer than its actual production life (the time period where it was being actively manufactured). B-52s were only built for about a decade before newer designs were in favor and it became just a matter of upgrading the ones already constructed. But the service life has been multiple decades because it's a very good design.