*first post to pinside * This is just an idea and I'm throwing it together without too much overthinking...anyway, I've groused a few times about how the comics collecting industry has a pretty good grading guide, but pinball doesn't have any standard system. (Coin collecting has this too, although I'm less familiar with that.) If pinball had a grading guide, maybe it would look something like this:
10.0 - NIB (new in box) - unopened straight from the factory.
9.9 - Gem Mint - opened and set up with no flaws. I'd prefer this over NIB. Played a few times just for testing.
9.4 - A brand new HUO game the day after Christmas. For EMs, possibly one that's a spotless professional restoration.
9.0 - HUO that's had excellent maintenance and care, or a game that's been flawlessly restored.
8.0 - Probably the best games you'll find in the marketplace most of the time. Very minor backglass flaking and / or tiny playfield scratches.
7.0 - Fully working with minor wear. May need minor maintenance like new bulbs or rubbers. Wouldn't take a professional very long to restore these to 8.0 or 9.0. Some minor backglass paint loss, reasonable cabinet scuffs and scrapes, loss of playfield paint around kickout holes and things like that.
6.0 - Still fully working but needs basic to intermediate maintenance. Very nice but has backglass and playfield paint loss that would need above-average skill to restore.
5.0 - Complete and mostly working but needs attention to be working fully. May need rebuilt flippers, cleaned steppers, or other maintenance. Noticeable paint loss but presentable.
4.0 - Turns on and lights up but doesn't do much beyond that. May have amateur repairs. These are the games that might just require a bit of tlc to be good "player's condition" games. Cracks in backglass repaired with tape, incorrect or missing rubbers, but all parts present.
3.0 - Non-functioning in present state. May be missing parts. Major paint loss. Restoration to fully-working game is probably beyond the purview of most enthusiasts.
2.0 - Missing major parts such as backglass. Will need donor parts from other machines to ever be working again, or is best used as a parts machine.
1.0 - Found next to a cow. Picture posted in group with caption "can you identify this game?" May have salvageable parts.
0.5 - Individual parts such as badly flaked backglasses and warped playfields.