system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do military vehicles have a longer period of usage than other vehicles?

By this I mean some planes that the USAF use were made in the 60s yet we are still using them today; however there are practically no commercially used planes made in the 60s anymore. Why is this?
gpt
Maintenance. Lots and lots and LOTS of maintenance. Most people don't realize just how much maintenance all types of military vehicles--and particularly aircraft--require. It's not at all uncommon to find aircraft, even new aircraft, that require tens or hundreds of hours of maintenance for *every hour* of flight time.

In the case of B-52s, those were all built between 1952 and 1962, and there are ~70 of them still flying. Damn near everything besides the airframe has been replaced multiple times, but those planes were just well-built to begin with.