I personally don't help with homework unless I'm asked. I do tend to look over math worksheets, because my DD8 is the kid who doesn't read directions or look at signs, so she could easily do an entire problem set completely wrong. But I try to limit my feedback to "You're doing those problems wrong. Read the directions and look at the signs," unless she asks for more help than that. (DD and I are also too similar, and we butt heads over perceived corrections. Explanations provided upon request generally work for us.)
FWIW, my DD has turned in several open-ended assignments where I felt she was both off-topic and not following the prompts, for which she got full credit. Teacher perspective is different than parent perspective.
