Posted by Lakeside on December 2, 2011 at 5:52pm
The issue is when a module or theme is updated it's advised to run update.php and then clear the site's cache.
Other than keeping track of the enabled modules and themes for the various sites on an excel spreadsheet what system are you using?

Comments
If you use drush, it's easy
If you use drush, it's easy to update and clear the cache for sites using site aliases. Most of my sites use the same modules so when I update one of those modules, I just updb and cc on all the sites. If it's a module that's only on one site, I just do it for that site. If I can't remember which sites use a module, I'll sometimes just do updb and cc on all the sites anyway, just to be safe. Only takes a couple of minutes for my 20 sites.
@aaront, Drush does sound
@aaront, Drush does sound like a good solution. Attempted to use it about a month ago, but then discovered something had been changed on Drupal that gummed up the works for Drush on a PC.
Do you know of a tutorial (for PC users) that is current?
Drush 5
The best thing you can do is to also try to get up to drush 5 which has had most of the Windows improvements. Drush 4 is generally acknowledged as not going to work on Windows.
From http://drupal.org/project/drush :
http://www.drush.org/drush_windows_installer
Drush with @sites and sql-query
You can run the following to see which sites use a particular module and where it's installed since you can have the same module in
sites/all/modulesand thesites/<sitesubdir>/modules(or in profiles, core, etc.):drush --root=/path/to/drupalroot @sites sql-query "select name, filename from system where status=1 and name='views'"