Why do we check spelling and grammar?

Answer 1

Because it is important to spell correctly and have good grammar. Bad spelling can result in something that does not make sense or means something different than what you intended. It is particularly important for formal documents and things you are creating for other people to read. It would look very bad and unprofessional if you have bad spelling and grammar. It also makes you look careless and that does not create a good impression. If you were applying for a job and had spelling and grammar errors in your letter and CV, a lot of employers would ignore your application. So it is very important to get your spelling and grammar correct.