I use Goldmine Grading System for 45s. Listen & visually graded.
NM = The vinyl is near perfect
NM- = Somewhere between VG+ and Near Mint. At most 1 or 2 tiny and light hairlines or scuff lines.
VG+ = Vinyl has been well taken care of but will have a few very light hairlines or scuff lines. Maybe some other slight imperfections like a rub mark. There should be very little to no background/surface noise when playing this record.
VG = Vinyl will have several light scratches or hairlines and light to moderate Background/surface noise while playing. Still a nice record but expect some crackles and pops.
VG- = Somewhere between VG and G.
G = Vinyl will have many scratches and scuffs with significant surface noise upon playing. This type of scratches will be very evident but should not cause any skipping during play.