Hello fellow YNs and YNH!á
What to collect. It's a decision that happens all the time that collectors REALLY have a hard time picking. Of course, you could collect everything you want to at once, but especially if you are buying and not collecting from circulation, that can be a huge problem, and none of your folders will ever be full. (This article was written for collectors of US coins, but the tactics can be used in other areas of numismatics as well.)
First of all, I like to make a list of coins that appeal to me. Maybe it's Morgan Dollars and Mercury Dimes, or Barber Quarters and Bust Halves. Just write it all down on a piece of paper. Then, go through your Greysheet and/or Red Book, and look at the prices of the key dates. Could you scrape together enough money for that one, go for it in low grade, or could you settle for the folder with a missing coin? Afterwards,álook at the prices of the simi-key dates. Perhaps you could afford a G-4 example of the 1909-S Indian Head Cent, but could you also afford the 1908-S? The Flying Eagle types? The price is one of the main reason collectors stray away from certain series.
Finally, if your collection idea has made it past all of those criteria, you lastly want to think of availability. If you are considering collecting Morgan Dollars, availability will not be a problem. I have never met a not-specialized dealer who hasn't had at least one Morgan in their stock. But if you are collecting, say, trimes, you might have a problem. If you only have one dealer in the area, they are most likely to only have a few in stock, if any. That won't help your date set.á
That's a lot to think about, and I'm not saying you HAVE to stick to these rules. I'm working on a Lincoln Cents folder, and there's no way I will ever fill the you-know-what slot. But, I still love the design, and hope to have the rest of the dates involved. Also, you can TOTALLY collect multiple sets at once. I do that. The only problem is, since I am working on a Ben Franklin Halves and a Indian Head Cent folder. Both folders need to have purchased coins. The problem is, I buy one Half dollar, then one cent, then one Half Dollar... so I won't complete either folder for a while. Use this as a basic guide. When in doubt, collect what you like!