At least one of the late-1980s/early-1990s Mac desktops and at least one IBM* enterprise-fleet-targeted desktop were designed for very fast in-the-field repair by corporate IT staff. By repair I mean "unscrew the case, replace the faulty component, screw the case back together, and get the customer back up and running ASAP."
I personally saw computers from both companies that had ONE screw, not counting customer-installed security screws/locking devices. Everything else was held in place by latches, friction, or other easy-to-manipulate no-tools-required connections. You could literally replace any one of the major components with less than 5 minutes of downtime once you'd done it a few times. Floppy drive, check, hard drive, check, power supply, check, motherboard, check, add-in boards, check, various cables, check, case, check. OK replacing the case might take 10 minutes but only because it requires moving all of the other components.
* IBM sold off its PC computing line to Lenovo in the 1990s or 2000s.