Not being a native English speaker I find spell and grammar checks to be an necessity. If I didn't use those I would misspell a lot. I spell perfectly fine in my own native tongue but English not so much. Then there is the intermixing of UK English and US English. Most foreigners are taught UK English and then learn US from TV and forums and you end up with a mix of sidewalks and pavements, z and s. Its somewhat confusing at times.