Actually, I have lost money selling some sets - "by the set".
It is easier and faster, but selling it in pieces or - "by the coin" - will usually get you more money.
I would bet that, for example, a
Mercury dime set will fetch what the semi key dates and key dates alone would fetch.
It would be as if the common dates would just get thrown in as far as the total price realized goes.
The reason we collect coins and complete sets I think, is because of the hobby and challenge and for personal satisfaction.
Nobody appreciates that more than yourself.
You complete a set for you.
It's almost like when people would come to my antique shop to sell me something that had a "lot of sentimental value".
They didn't want to hear me say it, but I had to inform them that I don't pay any extra for sentimental value.
It's not like on the "Road show" where the appraiser says about the family's civil war ancestor collection of buttons, tinplate photographs, letters and sword together add value as a collection, and worth more than being sold by the piece.
Unless you're somebody famous and/or your set has provenance and prestige, I think you'll lose in most cases selling them all together as a set.