Sports gear has no grading service, and the vocabulary it does use is refreshingly practical: it describes capability rather than appearance.
The three bands
Match condition — ready to use at a decent level, with no faults that affect play. Practice condition — usable, with wear that shows. Where most used gear belongs. Worn — usable with limitations, or needing work. Say what work.
Then the specifics, because the bands alone mean too little.
The specifics, by item
Bats — face marks, edge cracks, toe condition, repairs, whether knocked in, grain count if known. Rackets — frame chips, grommet wear, string condition and age, grip, and any crack at all, because a cracked frame is a dead racket. Shoes — sole and stud wear, upper creasing, inside condition, smell. Gym equipment — coating, rust, bearing noise, cable fraying, completeness of a stack. Balls — shape, seam, whether they hold pressure.
The sentence a buyer is reading for
"It is usable as it is" — or it is not, and you say what needs doing. Getting that wrong is what turns into a return. Describing sports equipment.
Specification is not condition, and matters as much
Size, weight, grip size, bore diameter. A perfect racket in the wrong grip size is the wrong racket.
Questions people ask
Is a hairline crack in a bat a fault?
Yes, and many bats carry them. Show it and say whether it has been repaired.
Does a fresh string job raise the grade?
It raises the value. Say when and with what.
Can I grade untested gym equipment?
No — say untested and price it so.