Shane Bradt of the UNH Cooperative Extension asked me why ArcGIS doesn't have an "auto-update" module to check and notify a user when a new service pack has been issued. Good idea. I checked and didn't find anyone else had suggested this, so here it is:
This idea has been merged with Check for Updates button.
ArcMap should have an option to check to see if a new service pack is available at startup like Microsoft and Apple and Adobe does.