I have a "cash" book that I have inked in the all of the demoninations and the dates of the series. Then I pencil in my best one with the date of my purchase, how much I paid and what the CCN retail value is that day. If I get more than one (like 1923 cents) I just list how many I have and put down the value of the one that I spent the most on. I take this book with me where ever I go so that at a glance I can see if I am interested in a coin upgrade or replacement. I have had the book for over 25 years.