Does apple always refurbish iphones before re-boxing them?

I'm getting a used iphone 4s. I want to make sure it's refurbished before I use it. I'm VERY VERY ocd about this stuff.

If you are so "OCD about this stuff",
you should have bought a new phone instead of a used one.

"Refurbish" has no specific definition;
it can mean anything from a full-on lab-test / repair process
to nothing more than reboxing with all of the accessories
that a new item would include.

To answer your question, they have a rigorious process and you will be find. I recommend you get a new one though if you can so you can have one all to yourself.