When does your WIP stop being a Straw Dog?

I learned a new word yesterday. From my federal- employee- husband, of all places. He runs a National Wildlife Refuge for a living, so I just did not expect him to drop a term in my lap that is so applicable to writing. But he's in the middle of a huge project that requires the melding of a lot of other federally employed minds. He said, "I love the term straw dog." I said, "Huh?"
And he explained: "You know, when something is just a draft, still open to changes. It's called a straw dog."
And m...