I ask myself those questions often. As I'm tasting the beer, would I be happy with it if I was served it at a bar? I was drinking a Session IPA I made, the recipe found here on line:
https://www.brewtoad.com/recipes/love-you-long-time-ipa
and I was thinking if it would be something others would buy. More malty than most IPA's interesting hop flavor and bitterness, but balanced.
As I pondered this, I drank two bottles in a very short time and wanted another. So I suppose it passed the would you pay for it test.
I've brewed many clones from the can-u-brew it series and then done side by side taste tests with the commercial examples and so far, my beer has come out on top 100% of the time. I suppose if there is a difference in taste, its not really cloned, but that's not the point, the question is which is the preferred beer. Its not really a fair comparison to the commercial example, mine is fresh and hasn't been transported around, theirs has been sitting around in who knows what temperature for a while.
Some of my experimental recipes I would not buy, although I haven't had to do any drain pours (yet). I started out all-grain, but did try a few "quick" extract brews that I would not buy, but I drank every drop.
I've become much more picky since I've been a home brewer. Many commercial "craft" beers are just mediocre. Better than drinking BudLight, but for what they are are charging, I just don't think they are all that good.
I think I've made a few "great beers", a Rye Saison, A Czech dark lager and a Belgian Quad that aged for a year. Most of my "average" beers are just as good or better than what I get at the local pubs.