I write, give or take, at least fifteen-hundred words a day, and most of it has to be in "PROFESSIONAL ENGLISH." The stuff that doesn't still has to be legible and easily understood. Correctly spelled things are easier to read
Suffice it to say, I write quickly, and since I don't have the luxury of using abbreviations or text-by-phonetics spelling, I write properly as a default.
Which isn't to say that my grammar is immaculate.