I have never done a 0% review, I think it would be really unusual for a band to put something out that I would find absolutely irredeemable. Even St Anger and other legendary bad albums aren't truly zero-worthy in my book. I think a 0% album should not only be very bad, but have a little extra oomph to truly deserve a 0. It should also lack the "so bad that it's good" factor imo

What, for you personally, does an artist need to do (or not do) for a release to deserve a 0%?

Agree about the combination of factors, I think it's not only a matter of "objective" (as much as it may mean) lack of quality, but it also should come with that something that pushes you to downright hate said album and never want to hear it once for the rest of your life. It might be the vocals (as it did for my case), the themes (like for NS bands, or just bands with fuckin' stupid lyrics or toxic attitude...), or whatever. "So bad it's good" albums surely do not qualify, because that would imply you enjoyed them to some extent, after all.

That's why it's also extremely subjective, I feel some of us get irked quickly and give out a lot of 0%s, while others could be more lenient and tend to look at the positives.