Here’s how it works:

There’s not much of an interface for this one, you simply go to a sheet
and run the command.  It will then go into a selection mode asking you
to “Pick viewports in the desired order.”

Download Viewport Renumber 2013, 11.48 kB

Download Viewport Renumber 2014, 11.92 kB

Original post by Tim Logan:

Revit Viewport Renumber Tool | LMNts

There are quite a few renumbering add-ins available for Revit.  This free little package from CTC includes a tool to renumber both Rooms and Doors…

Room and Door Renumber for Revit 2013 – CTC

Sequence numbering on doors numbers doors independently. The tool remembers the previous door’s number and will maintain the proper sequence on subsequent doors.

More info:
Revit Renumbering Video Tutorial – 2:00
pdf Revit Renumbering Product Information
Revit Renumbering available on Autodesk Exchange:
You can also get Imaginit Room Renumber on Exchange at:
Autodesk Exchange Apps