The ' Red Book ' 2012 page 9 has condition definitions. Also every different coin section has conditions i.e. Shield Nickels, Liberty Head nickels, Indian Head or Buffalo Nickels, etc, etc, If your coin fits into MS60 or higher you might want to submit it to a TPG (third party grader) such as NGC, PCGS, or ANAX.
If you do not have the requisite knowledge yourself then you ask somebody else who does. You will however get a wide range of opinions when you ask. Consider, depending on what the coin is, it can cost around $40 (maybe more) just to get the coin graded and slabbed. So when you take into account what the coin cost you to buy it, and then add in the grading fees - it may not be the wisest choice to spend the additional money for grading. So a general rule of thumb is that the coin needs to be worth X amount of dollars before it is economically feasible to get it graded and slabbed.
