User blog comment:Blood Reaper/Small 1.4 update/@comment-67.234.81.246-20120110125620/@comment-4081131-20120117035910

A month? Pretty sure I've had them respawn after a few days. Week at most.

Also, maybe they'll go the kludge route like Obsidian did for New Vegas and have a place you can go to force remove any follower.