Coin errors are both the easiest thing for collectors to understand and the hardest.
Everybody understands the concept of something going wrong. However, from there many tend to slide off into silliness.
You see cutesy stories or descriptions over time that are written to hype the current value of something online. These stories for the most part don’t stand up for long and buyers end up with a lot of virtually worthless cutesy coins.
The errors that stand the test of time tend to be immediately identifiable by all, have an essentially defined number that exist, an explanation as to how they were produced in a manner that is replicated over and over again in the same way and they can be seen with the naked eye.
What’s identifiable by all? Well, classic errors are 1943 cents that were struck on the copper-based planchet rather than a steel planchet. Catalogers maintain a census of them and when they come up for sale, as a 1943-S copper did at the Heritage Long Beach sale, bidding goes to the moon, in this case $207,000.
Another easily identifiable error is basically what introduced the mass of collectors to the error concept as an acceptable collectible. That is the 1955 doubled-die cent. There are a few thousand of these and they are listed in the popular price guides.
Again, collectors can easily distinguish the doubling in the date. The error experts know how they were produced so all of them are virtually identical because they were made from the same obverse die, which had the doubling on it. The doubled-dies are not struck twice.
If you need enormous magnification to see something, it drastically erodes value.
Another thing to keep in mind is that any errors on proof coins tend to be more valuable than the same error on a circulation strike because quality control is much higher for proof coins.
Now don’t get me wrong, there are many collectible errors that don’t necessarily fit all of these criteria, however, their existence tends to be explained in very dry and technical language rather than cutesy stories. Prices for the most part are reasonable. In other words, if you find one, they won’t make you rich.