I keep seeing posts about people upgrading without reboots. I sometimes think everyone is punking me. Is this a thing? How does one accomplish this?
Depends if the update needs a new kernel, not all updates do.
If you wait long enough to update you will likely never see reboot-free since updates are from installed to most recent available. As soon as there is a changelog that ships with a "src" change in the list that requires a reboot.
21.1 -> 21.1.1 reboot
21.1.1 -> 21.1.2 no reboot
21.1.2 -> 21.1.3 reboot
21.1 -> 21.1.3 reboot
21.1.1 -> 21.1.3 reboot
Cheers,
Franco