How long can a manufacturer say a product is "NEW!" ?

I see alot of products that say “NEW!”. Some of this stuff has been around for awhile and really isn’t “NEW!”. Is there some kind of FTC rule or something specifying how long companies can put this on their packaging?

The FTC rule (unless they changed it recently) is six months.

Note that any changes to the product allow you to use “New” again for six months.