wow I've got so much better at this compared to a year ago. I went through introducing CI, replacing Nix expressions, switching to hpack, writing a test suite (in doing so, reverse engineering half the yesod routes quasiquoter), and fixing two dependencies' bounds, in a day.
I found a comment that said "wtf, how do you do (x)", which was written after struggling pretty hard, and I knew the answer in a few seconds.