When looking for different parts for my 2007 Ranger I have seen the statement "to 8-29-06". Just wondering if that was the date Ford quite making the 07 model and went to the 08 model? Thanks

 

My guess would be it's the date Ford ceased making the 2006 models and began making the 2007.
I base my guess on September being the quintessential starting month for the following year. Indeed, there were plenty of exceptions. The 1967-and-a-half Pontiac Firebird comes to mind first.
It would be called a "Year break".
Part changes and applications for in-production vehicles were also marked by serial number. Ex: Part UVW to chassis # 432,689, Part XYZ from chassis # 432,690.
This is called a "chassis break".