How do you as a collector define “Rarity”?

[Baseball Rarities]

Here is the scale that has been used in the coin market for years:

■R-8: This is a unique coin; only 1 exists
■R-7 High: A coin that’s excessively rare; 2 to 3 exist
■R-7 Low: An extremely rare coin with 4 to 12 remaining known
■R-6: A very rare coin with 13 to 30 known specimens
■R-5: 31 to 75 coins exist, classifying it as rare
■R-4: A very scarce coin with 76 to 200 examples left
■R-3: With 201 to 500 estimated pieces, this is a scarce coin
■R-2: A coin that is not common, with 501 to 1250 coins in existence
■R-1: With at least 1251 coins remaining, this is a common coin