What makes carpet more or less stain resistant and will it wash off?

Here is a transcription, if you prefer to read instead:

“One of the biggest questions we get on a daily basis is, “What makes carpet stain resistant or not?” Different carpet fibers are more stain resistant than others. Some of them are porous; some of them are not. The ones that are not really don’t need any kind of stain treatment on it. Sometimes they will put a Scotchgard on the surface of that fiber, sometimes they don’t. It really doesn’t help all that much. But the ones that are porous definitely would need something to be able to maintain its fresh look all the time because if it were left porous then it would absorb any kind of liquid stain, in general.

The cleaning of carpet, whenever you have that professionally cleaned, takes off about 15% of that Scotchgard or Teflon or whatever stain resistance put on there. So that means that if you clean it and 15% of it comes off every time, if you get it done every 24 months, that carpet should last anywhere from seven to ten years with a stain resistance on it. The other fibers like polyester and SmartStrand that do not have any pores whatsoever, you never have to worry about that coming off because none of it was ever put on.”