Updates that do not require a reboot should run reroot
Hit a situation last night that seems like it might be rare but worth accounting for in the future: I updated a VM to test a change, but the update was base only and did not require a reboot. The previous copy of a page changed during the update had apparently been cached by the system and the updated page was not being presented to the browser. After restarting php-fpm it worked as expected. That should probably be done for any upgrade that touches the base pkg to be safe, and perhaps also restarting lighttpd would be a good idea.
Similarly, if it's not too hard to detect, it would be worthwhile to restart a daemon/service if it or one of its required dependencies is updated.