I give each magazine a grade closely modeled after the grading system used by the Overstreet Comic Book Price Guide. I use a "+" sign to indicate a magazine slightly nicer than the assigned grade but not good enough to make the next higher grade. Most of my magazines are in the top 3 grades listed above the red line.
I don't use Mint because to many people think that means perfect. Even brand new magazines at the store have bindery defects and shipping and handling defects. If I grade a magazine Near Mint it looks unread, like it did at the store or very close. A slightly bumped (not creased) corner, 1 or 2 minor spine stresses, very minor handling wear are allowed.
A Very Fine magazine is close to Near Mint with almost full cover gloss, appears unread, and lays flat. It may have a very lightly creased corner, 3 or 4 minor spine stresses, a little extra handling wear. Still a beautiful copy.
A Fine magaizne is still above average but has accumulated enough minor defects to take it out of the higher grades. Still a solid, collectible copy.
Good magazines look very tired. They are complete but look like what you see in the waiting rooms at barber shops and doctors' offices. They are usually graded "Fine" by non-magazine flea market dealers and other amateurs.
Fair magazines are good for toilet paper and stacks of them make nice homes for mice and silver fish. If you're a mainstream antique dealer with no knowledge of paper collectibles "they look nice for their age."
Hit the road Jack.