I've never completed a date set. I'm trying to do one. Business and proof strikes At leas the collectable dates as the last 2 would be $500k for the first and 2+ million for the second. That's why I became a dealer. Trying to do too many different things and so many pretty coins. So I'll do my type set and my trade dollars and the small eagle half and the 78-cc trade are going to be very tough especially with my surface requirements and may try to do the early flowing hair and bust dollars too someday. Of course without the 1804. The 1794 is bad enough
Years ago collecting by sets was the thing to do. I think it really started with the circa 1938 Whitman coin boards.
Generally, I collect by type, and anything that appeals to me. Sometimes I'll make short sets of a series I really like, such as the first 10 years of seated dollars, or the pre 1940's Walkers. And I'm almost done with a full date set of Bust halves (less that pesky key date). And the circulation strike Trade Dollars, of course. And the Monitor tokens. And some HTT's.
The supply of the 1877 and 1878 may or may not be the same but the mintage doesn't allow anyone to conclude anything. Since there were fewer or far fewer collectors in the 1880's and 1890's than later, I am dubious the 1877 would have been saved to the same extent as later "key" dates. It is however, still a common coin. Also, if by "estimates" you are referring to PCGS Coin Facts, there was a thread here but I never commented. My brief review of the data leads me to believe it is reasonably accurate on some coins (especially the most widely collected 20th century series) but not accurate for earlier coins.
As a collector of early gold, it's not about the "key date" issue... since they're all literally key dates in terms of the remaining existence of attractive, original coins. I like the pursuit of a date set because at that time, the mint was going through many struggles, whether it be die steel shortages, or yellow fever outbreaks. Because of this, the coins could vary greatly in quality, strike, and design nuances from year to year... same thing with early branch-mint gold. Each branch mint was "new" to the game while by that time, Philly had "been at it" for over 40 years. Every date varies... from mintmark placement, to lettering, to date sizes... and particularly -- quality of strike... each one has a story to tell.
Hey, collect what you like! Some people like to do type sets (as you do, apparently) - they like variety, they like being able to choose what constitutes a set, they like getting a bit of everything. Other people really like doing date sets of a series because they enjoy that particular design, or like the series, or have some affinity for it. They like going deep into a single series, learning everything about the history of it, and the subtleties of each date and mint. There is a defined goal for the set, something to work towards - and that makes some people happy. I have done both. I built an award winning set of Franklin halves, and thoroughly enjoyed it. I am now building a type set, and am having a great time doing that as well.
Another issue is the extreme length of the more modern series. I like early Washington quarters, and there aren't any unobtainable keys, but I have no interest in collecting 30 years of clad releases in a Dansco. Just shoot me if you ever see me at a coin shop looking for a 1994 quarter and paying 35 cents for it. In the end, the collection might look nice but it'll be 50% spending quality coins. If I could find a nice folder for silver-only, I think it might be fun though.
I really hate creating and filling albums. Not my thing. But, oddly enough, I like buying almost complete sets at bargain rates and finishing them. Call me crazy
Others have given the reason here, tradition. I too believe it will decrease in popularity later and as a result, the prices of most coins in these sets will stagnate or decline. This especially applies to "key" dates in average to lower circulated grades which are anything but rare and are exorbitantly overpriced for their numismatic merits versus coins which are otherwise acknowledged to have a lot more going for them.
I already see that happening. For example, I just sold on Ebay a couple of low grade semi keys I bought back in the 90's (1916 Walker and 1921 Mercury) and barely got my money back out of them. The coins I bought during that same time that have genuine numismatic scarcity, however, have held up a lot better, with some worth multiples of what I paid. Just look at the new acquisitions people post on this forum. We don't get very excited about well worn key dates. Most of us want to see some high grade monster toned bling. The advent of digital photography is probably accelerating this trend. Now when we buy something pretty we can show it off.
Albums are available from Intercept, Littleton, and CAPS (as well as the Dansco 7070 if you want to buy used and pay a premium for it). You can also get holders from Capital Plastics, or you can make your own.
Sometimes it is kind of cool to complete a set. This one of Circulation Strike Wheaties. I often think about what was going on the year a particular coin was minted.
That is one beautiful set of pennies - gorgeous! And none of them certified. I like that too. I once had a date set of Carson City Morgans, all raw. When I decided to sell them I sent the best ones in for certification, which certainly helped sell them - but it was nice having them all raw (in airtight holders) togerther - so you could see them more like the pieces of history they are.
Here is a link to the same subject. http://boards.collectors-society.com/ubbthreads.php?ubb=showflat&Number=7938281&fpart=2 One example I used was the 16-D dime which at the time sold for $411 in AG-3 and $705 in G-4. If this were any other date in the series or practically any other coin, it would be described as "dreck". Most of this coin are in similar grade and I suspect that most current owners acquired this coin a long time ago when it was (a lot) cheaper. But even if not, I expect it to be a huge financial loser in the future, and so will other "key" dates like it.
I collect primarily by type, but I do date sets for the types I love the most. If you like a particular type enough, a date set is a great way to collect multiple attractive examples of the type. It also provides enough constraint and variety to make it interesting to collect.
For those of you that have tried to complete a date set and gave up, do you appreciate or envy those that actually do complete the set? When I see a completed set, I know the dedication it took to do it and have an admiration for the set and the individual who completed it, at the same time holding a competitive envy for the coins in the set that I don't have.