Coins With Minor Defects

An article, whatever it is, is only worth what somebody is prepared to pay for it. If a dealer offers a coin with minor damage at a price that he thinks he can sell it for, it is still up to the buyer to make up his mind if it it is good value for money, for whatever reason to the buyer.

If the buyer is having some trouble to make that decision, the best thing to do is investigate the prices of near equivalent coins and compare the 'bargain' of the coin you are offered to the near equivalents.

If you still have doubts, don't buy.

This process happens all the time with ancient coins. VERY FEW of them are perfect.

Mostly due to the eye doctors back a few thousand years ago, never could get the prescriptions right. The workers at the Mints had a lot of problems making dies and punches with those lousy glassesb they were wearing. And the contacts back then too were of poor quality. Worse yet was the material the Mints had to order from companies like the ones that make our roads.
As to the problems with coins. There is a big difference in Post Mint Damage, PMD, and Mirt Errors. As an example look at the famous 1955 Lincoln Cent Doubled Die worth way, way more than the most perfect 55. 3 Legged Buffalo nickel worh way more than a normal Nickel. Even many rumble about a reverse rotated coin. Is it worth more due to a Mint Error or worth less due to it being irritational.
Naturally a coin that has been bounced on the ground is now worth much less than one never bounced. Using a wire wheel to clean a coin too, lowers it's value. But then too, even that could depend on how much damage is done.
To many factors and differences to answer this one exactly.

Obviously the YMMV answer doesn't help a lot. Sure it depends on what kind of defect and how much that detracts from the eye-appeal etc.

Most of the dealers I've talked to about this subject tend to say they price and buy problem coins at around 2 grades lower than a problem-free one. So that might be a "very loose" rule-of-thumb to use and it is where I tend toward when considering such coins - usually lightly cleaned or rim dings on high grade expensive coins I wouldn't be able to afford otherwise.

But I've seen some who want 90% or more of the retail for some problem coins and others willing to dump them for 20%. Defects make for a lot more range than problem-free coins and those can have a big range already.

JMHO

Completely dependant on the type of problem. Again, so much depends on if PMC or Mint error. Note on page 416 in the Red Book there is a list of approximate values for error coins. Naturally this is based on Mint type errors, not PMD.

Completely true. And with coins damaged after they are minted, so much depends on how much is done. A really small dent may be missed completely by some and yet someone else may rejecct that as completely damaged.