I may be a poor person to ask for an opinion on whether to include "varieties" into your collection. I am almost exclusively a Vicky Large Cent variety collector, so I collect any of these anomalies that are easily seen with bare eyes or 4-6X max. I agree with 007 above, in that you should decide what you want to include. If I collected modern, post-1920 coins, I would include most of the popular varieties if they were due to change of fonts, monarch portrait, spacings between the design with the rim or beads/denticles, and letter or digit spacings, etc. It just depends on how deep you want to wade into the variety waters. If there are some nice offset doublings, they are nice to have, whether or not they are a variety or an error. I wouldn't leave open spots for some mint-manufactured oddities that were not for circulation, for example any "dot" coins and the like. Expand as far as you want, or not.