they understood me" is not a pass

I keep seeing the argument that broken English is fine as long as people get the gist. But in writing, especially for tests or work, every missing article or wrong tense shifts meaning. Band 7 requires precise vocabulary and grammatical range — "close enough" loses you marks. If you write "I need an advice" in an email, the reader notices, even if they don't correct you. Correct once and it stays corrected; guesswork builds bad habits that cost you later.