@John. Greasy is pretty close. I basically serialize any coins I keep or investigate so I can uniquely identify them. That way I don't confuse this 1971D Kennedy with any of the others in my collection.
The first part is the date I started working with the coin (yyyymmdd). The first coin from that day is -001, the 2nd is -002, and so on. This is the 2nd coin I investigated on January 17, 2020. It also helps me keep my pictures organized. I rename the pictures accordingly (20200117-002 Obv full, 20200117-002 Rev full, etc). This keeps me from posting the wrong pictures by mistake.
This is probably overkill, but after a few days I find I confuse coins with each other and forget why I started investigating them. This system allows me to quickly reference my notes and keeps me from constantly re-evaluating coins to remember what makes it unique. I also find this system especially valuable when selling on eBay.
Thank you all for the input on the Machine Doubling
. I am putting this one back into the spend bucket.