10 point scale neen there

To those Vaporents/ettes familair with the 10 point rating scale (e.g. 9/10) for how baked you are: Unless you've visited such a place in the past, how do you know if the stone you've got on is only a 4 or an 8? I'm not sure I've experienced a 10/10, so do have have any business stating "Oh...