No, there is no standardized system. We do have a rating chart that trade members are free to use if they so choose, but many members choose to devise something with verbage that is more specific to them.
I would suggest with any rating system, that you still be consistent throughout all your listings and add as much detail as you can on condition.
For example, if your rating system says (and i am just making this up) Pristine, Pretty Decent, Fair to Middling, Poor/for study only with each situation explained, you don't have a listng that says "Great!" with no explanation.
(that really confuses folks)
