All excellent points
Chris The Story Reading Ape's Blog
on Just Publishing Advice:
As a writer, you need to understand the importance of fixing your spelling errors and grammar mistakes.
Most programs do have a spell checker built in, but not many have a grammar checker.
There are many ways you can check your grammar and make sure you publish content that is correct and engages your audience without the distraction of improper writing.
If you are not familiar with the common grammar mistakes, you need to do your research first. Once you are aware of these, you have a better chance at identifying the uncommon ones.
There are many free grammar checkers online, but you have to be careful when selecting one.