I'm not sure if it fits your question but I've always regretted the apartment building I put my characters in, it just doesn't make sense architecturally considering where the doors are and where the windows are?? I didn't expect so much of the series would be in the apartments and specifically on the stupid ugly couch that I'm SOOO tired of coloring. I just wish I put more thought into making it a more interesting setting for the characters.
I recently switched to Clip studio which has a lot of 3D assets of apartments and I really wish I had that earlier bc they look so much better than the one I designed.
But with characters, I've managed to avoid this for the most part by making everything into a brush or really limiting certain things, like my characters change clothes daily and so I'd have certain colour pallets they like to wear, I make pattern brushes so it's easier for me to put patterns on their clothes. Not to mention brushes for the fences, books, shelves, etc. Now that I switched to Clip studio there are ready made brushes for anything so it really has made my life a lot easier and I'm able to make sure the art looks good without worrying about the smaller details.
If you can make something into a brush or streamline certain things then do it, even if it feels like it's too late because it'll be better for you in the long run.