With just a few exceptions, coins of this type were made in fairly large numbers for their time, and collecting this series by date is a realistic goal, at least for those seeking circulated pieces. Augustus Heaton’s 1893 monograph extolling the virtues of collecting the branch mint pieces gave rise to a limited market for these coins, and a few dozen numismatists purchased these coins directly from the respective mints at the time of issue. For most collectors of that time, however, a single Philadelphia Mint proof of each date was sufficient. Thus, mint state examples of the early dates, particularly the New Orleans and San Francisco Mint issues, are scarce. Barber Dimes were the oldest coins of this denomination still circulating in the 1930s when the first inexpensive boards and folders for collecting by date and mint appeared on the market. Countless, well-worn pieces were thus saved for posterity, and the collecting of this series in its entirety has enjoyed moderate popularity ever since. There exists some interest in seeking out varieties for this series, though there are few that bring much of a premium. One notable exception is the 1905-O with Micro O mintmark. The prominent varieties are included in VarietyPlus and attributed by NGC. Notables include the 1892-O with doubled date and the 1893-S with dramatically repunched mintmark. Additional varieties are found within the books by David Lawrence and Walter Breen, but there’s only modest collector interest in them at this time.