Why grades exist at all
Buying a used paddle privately means trusting a stranger's adjective. One person's excellent is another person's beaten. The grade replaces the adjective with a procedure: the same twelve checks, applied to every paddle, by the same hands.
The reference points are a certified pre-owned car or a graded watch, not a repair shop. Nothing is restored. The grade tells you what you are getting so you can decide whether the price is fair.
What the three tiers mean
Mint is the top tier: a paddle that has seen little or no court time. Face texture is essentially intact, the edge guard is clean, and the grip is either original and unmarked or has been replaced. These are usually paddles somebody bought, hit with a handful of times and moved on from.
Like New is a paddle that has been played and looked after. There may be light marks on the edge guard and minor wear on the face, but the bite is still there and the core is sound. For most buyers this is the value tier. The performance gap to Mint is small and the price gap is not.
Excellent is a paddle that has been played regularly and shows it. Visible cosmetic wear, a face with measurably less grit than new, and a grip that may have been changed. It plays properly or it would not be listed, but you are buying a working tool rather than a nearly new one.
What the twelve points actually check
The inspection covers the things that decide whether a paddle is sound and the things that decide how it plays: face texture and wear, core integrity, edge guard condition and adhesion, handle and butt cap security, grip condition, weight against spec, and structural checks for delamination and separation.
Most of it is not visual. The core checks are done by hand and by ear, because that is the only way core failure announces itself. A paddle can pass every visual check and still fail here, and that is exactly the scenario the process exists for.
There is a floor. A paddle below it is declined rather than graded down, because a dead paddle is not a cheap paddle. It is not a paddle.
Which grade should you buy?
If you are buying a paddle you intend to keep and play seriously with, Like New is usually the best value in the shop. You are paying a meaningful discount for cosmetic history rather than for reduced performance.
If you are trying a shape or a brand you have never played, such as an elongated handle, a thermoformed face or a heavier swing weight, buy Excellent. It is the cheapest way to answer a question about fit, and if the answer is no you have lost very little.
Buy Mint when the model is one you already know you want and you intend to keep it for years, or when you want a paddle that looks new because it essentially is.