Doing "Sets" Of Coins Without Key Dates?

I usually prefer to do business strikes only as well most of the time. That is how my Lincoln Cent set is.

With my Jefferson set, I opted to do business strike coins only initially. However, sometime later, since I already had some proofs, I decided to complete the circle and add all the additional proofs. It's a very good set and I'm glad decided to do the proofs. I have all the proof nickels from 1956-2005, and I am in the process of obtaining all the modern ones from 2006 and newer, as well as whatever I can manage to purchase from 1950-1955.

Though I do have some other proofs, I generally don't consider them personally a must.

Sad, but so very true. I am now mainly into proof & specimen Canadian coins and mint sets. Can't escape!
PS: also this year, silver Canadian Maple Leaf bullion. (without Privy marks)
I have the 1867-1967 Royal Canadian Mint set missing the $20.00 gold coin (for now), my example of a set without a key coin.

My philosophy has changed since I was a 10 year old kid plugging holes in those Whitman folders in the 1970's. Back then I was focused on filling as many of those holes that I could afford...and through roll searching. Then life happened, wife, kids, unaffordability. Now older, I focus on bargains. Some people here know I spend most of my time on ebay and it pays out. About 10 years ago I bought a Whitman folder (only missing 1909SVDB) for $107.32. Kept the 1914D (good) and 1931S (fine) and swapped out 5 other AU for my lower grade and resold the folder for $200. (so essentially I was paid about $85 to take two key dates off this guys hands). Another deal about 5 years ago, a Seller sold a complete date/mm Indian Head cent folder, and a complete date/mm Buffalo nickel folder (no acid dates). I ended up paying $85.50 for both after he refunded some postage. (1877 Indian has a slight bend but the 1909S should straight grade).
I guess what I'm getting to, is do the best that you can now, you never know what lies in the future. You may stumble into a deal that you weren't expecting and be able to fill some of those keys. Don't lose any sleep over a hole in your Dansco.

You could just buy recent Wheat cent proofs and flip them to show reverse in those holes. Then the hole is filled with a real Wheat cent, but it is obvious that it isn't the key date coin.

a novel idea Brand!

It is out of your price range until it is not.

My Poland OFER (One From Every Reign) would require paying a few thousand for a coin of Wladyslaw IV, as he only struck thalers, half thalers and gold, all relatively rare.

Not losing any sleep over it, and not regretting that I ever started that collection.

I will take that as a win!

You medieval and ancients guys have the patience of the saints.