Carpet Protector – What’s it best for?

I just read an recent article in one of the cleaning magazines that suggested the very same thing, include the stain protector in with the cost of cleaning. I don’t include it in mine, but I have 90% of my customers get the protector. I charge $.13 per sf and will go as low as $.08 on occasion if the job is large one or if it is a church or govt entity.