In my case I am trying to get a roll of each year/mintmark combination plus enough to fill the books that I have.
Starting to get hard to find any that I still need for my first roll of any date/mintmark combo though as I pretty much have the easy dates filled. Down to the key dates, the war nickels, most of the S-mints (half of which I am close to finishing), and a couple others that I am close to finishing. According to my tracking sheet I am at a little over 87% complete from 1938-2006. Only roughly 830 nickels left, 340 of which are war nickels. There are about a dozen or so that were recently found that I have not entered yet. Also, I only count those which were issued for circulation (including common varieties such as 1941-S large S) for rolls (proofs do not count).
Trying to do a similar thing with the other coins as well, but other than Kennedy halves (which I have complete rolls from 1964-2002) or maybe the SBA or SAC dollars (which I have never really searched), jefferson nickels are the easiest to complete through CRHing.
I also save any additional pre-1960 nickels I find because they don't cost too much at least at any one time. Though I have over $100 worth of pre-1960 duplicates above my rolls.
