That is a good point! I guess that it is tradition, and because so many would think that it would be more convenient if ancient coins had dates on them.
Think of the dates on coins as expiration dates, not to be used beyond that year unless you need the money.
"there doesn't seem to be a pressing need" Har-har Seriously, I really like your question and don't think it's stupid at all. Were dates included on US coins for the same reason(s) in 1794 as they are now? I can imagine a sense of pride in commemorating a country's early beginnings by dating its coinage. But foreign countries much older than ours have consistently had dated coinage. Is it primarily a matter of tradition? Maybe there's always been a fiscal reason for including dates: the mint needing to track how many new coins were needed to replace those lost to damage and wear in circulation. At any rate, certainly the US Mint realized at some point that minting dated sets would bring in revenue from collectors. All just speculation; maybe someone can correct me. Personally, not only do dates seem antiquated, but certainly the cent and maybe the nickel as well and, eventually, cash in general will be antiquated as all transactions become digital. (Btw, I read through the older thread on this topic and found interesting info and opinions but no clear answers, particularly to why there would need to be dates for every year of production. Certainly I can understand a date to acknowledge a design or metal composition change—but then again would anyone but collectors even care about these?)
Actually, they're "use by" dates and start to rot thereafter. However, rather than send them to a landfill, PM me and I'll send you an address for recycling. Cal
THERE ARE NO STUPID QUESTIONS...I will guess that the Mint can keep track of production, and maybe to help prevent counterfeiting? I think collecting was a serious hobby by some in the beginning...now that I think about the question, I would appreciate some accurate answers.
A zillion reasons: internal and external auditing, tradition, more direct sales to collectors, artistic and thematic design, anti-counterfeiting, coin longevity monitoring, keeping engravers happy, composition indicator, public expectations, political tinkering, etc. Cal
The Mint has to make money so when you take $.07 of metal, press them together and stamp $1.00 on it they just made $.93 cents. What a profit. The cost of storing them does not count, that's another matter.
Some ancient coins do have "dates" of sort on them. For example, Caracala loved to put dates on his coins. The XX on the reverse dates this to the 20th and last year of his reign, so we can narrow the strike date for this coin to a few months in the year 217 CE. While others, you'd be lucky to narrow to a few decades or centuries, like this Islamic issue of the Almohads. It would have been minted sometime in a hundred year period between the 12th and 13th century. I've seen some ancient coins that can be dated almost precisely to the month they were struck, and others where all we know for sure is that it could have been minted any time within a 300 year time span.
I appreciate your answer in that thread, along with some comments by others, that give some historical background for dates on coins. But these answers don't really address our more contemporary situation. Why does more recent coinage—say, US coinage since the advent of the Industrial Revolution or the 20th Century—need to have dates? As the OP asked, why go through the expense of changing dies on each denomination every year to reflect a new date? Your answer that "our law requires it" doesn't really address the underlying reasons or needs of such a law in the first place. I'll speculate again that the mint, er, "updates" its coinage 1), because new dies are, relatively speaking, not that expensive to create, 2), because it helps them to monitor production and loss and 3), largely due to inertia (or "tradition").
So then the question becomes, "Why does our law stipulate that coinage must be dated?" The real, and interesting, question is one of rationale, not formality.