I am working on Lincoln cents from 1909-1958 (not counting errors or varieties). I am approximately 75% complete. I think it will take me another year or two to complete the set. I chose to pursue this set because Lincoln cents are ubiquitous, I like the wheat reverse, and there are almost 3,000 varieties to find as you go. Money is the primary obstacle in my way to completing this set. Also, I am trying to put together a circulated unslabbed set so I search bags, and some of the more rare ones are hard to find (hence, rare).