Lincoln cents are graded by wear, remaining design detail, surface quality, color, luster, contact marks, strike, and overall eye appeal. Although it seems very daunting - and perhaps a bit overwhelming at first, the process of grading Lincoln cents is actually rather simple once you get the hag of it.
On circulated coins, the amount and location of wear are the most important factors. Small hits, abrasions, and other signs of wear and use are overlooked for circulated grades in progressing size and severity as the overall grade of the coin decreases and the wear increases.
Because there is no wear on mint state coins, we have to use a different approach. Mint state grades are determined by luster, marks, strike, color, and preservation. These factors are subjective, with professionals allowing different amounts of each causing one sources grades to be different from another. Neither is necessarily wrong, they are showing that their standards are different in each part of grading a mint state coin.
