When your ArcGIS Desktop licenses at a given level are all checked out, you get a "All ArcGIS for Desktop XXX licenses are in use!" message. You then have to go to ArcGIS Administrator, fidget with the interface to determine which other license levels are available, select one and then restart the desktop app.
If you share various licenses at different levels you probably run into this issue at least occasionally if not often. Why can't the desktop application check if there are other avialable licenses in the same license manager available and prompt me to select one and move on? This would make the situation so much more fluid and much less curse word inducing.
At the very least prompt me to "auto open" the administrator app so I don't have to dig thru the start menu for it.