I find the output of a no-op checkrestart run at the end of each apt session to be quite annoying. On a fresh Ubuntu Server 21.04 system, all apt invocations end with:
Processing triggers for man-db (2.9.4-2) ...
Scanning processes...
Scanning processor microcode...
Scanning linux images...
Running kernel seems to be up-to-date.
Failed to check for processor microcode upgrades.
No services need to be restarted.
No containers need to be restarted.
No user sessions are running outdated binaries.
ubuntu@ubuntu:~$
… which doesn’t seem to provide much value. There’s also a long delay after the “No user sessions” line.