I have it in my head that most Jefferson Nickels aren't worth keeping unless they are: 1) War nickels 2) On this short list: 1939-D 1942-PD&S 1943-PD&S 1944-PD&S 1945-PD&S 1950-D 2009-P&D 2010-P&D 3) In at least AU or BU condition 4) Errors 5) Henning counterfeits Is that about right?
Don't forget the 2005-P. I'm not sure if I'm getting the story correct, but I hear that most of the mintage ended up outside of the US for some reason, and now they are bringing pretty decent change for nice examples. Also the 38-D is a keeper.
Collecting Jefferson nickels based on their mintages is a bit subjective but a few other dates I would consider saving in "average" condition that haven't been mentioned from the other posters are coins from 1946S, 1949S and 1958P.
I am a sad case. I have kept hundreds of unusually nice Jeffersons of almost every date. Going by the Red Book the above dates are semi key and key dates and worth keeping just for that reason. There are common dates tho that are not so common when found well struck and with a good step count. Some dates generally have little or no step details at all.
So if I have a whole roll (40) of 1940 Jefferson nickels, for example, they are still only worth $0.05 each ($2 total)? (Or any other "common", high-mintage year pre-1950) Edit: I guess the simple fact that I can amass such a quantity over such a short period of time (less than a year of not-that-serious CRH'ing) speaks to the fact that they are only worth a nickel each...