"It is not fair that people judge others by their mistakes."
Well, did you notice the mistake or do you think that this sentence is correct?
The sentence has two major errors (which when spoken seems correct, but when written has a different meaning).
Firstly, let's see what the correct sentence should be - "It isn't fair that people judge others by their mistakes".
Just because 'fair' and 'their' are homophones, people can easily get confused with them. While speaking it is fine to some extent, but while writing, it goes unnoticed.
CHECK GRAMMAR FOR SENTENCES
The first step is knowing English Grammar errors
These grammatical errors can prove to be bad for a piece of work. As a reader will read through the piece, he/she will pay attention to these errors and will have to struggle to understand what the writer wants to say. At some point of time, a reader may lose interest from the piece and this writer's work will go waste.
It is always suggested that one should check their copies for any sort of grammatical errors before making them available to the audience. When we say grammar, it has many elements included like tenses, punctuation, spellings, and others. For a layman, it may get a tough job to go through copy again and again looking after for such mistakes.
Trust the experts in checking Grammar
On the other hand, when a copy is given to an expert, who is trained for this, he/she knows what to look for and how to look for it. They are able to correct the copy instantly and with ease. They are well versed with the grammar and have a habit of doing this job on a daily basis which makes it easy for them to spot errors.
A full stop can make all the difference!
Have a look at another example that will help you to understand the need for a grammar check before sending the copy to the audience.
Let's eat Grandpa.
Let's eat, Grandpa.
Both the sentences have exact words but just the placement of a comma changes the meaning of a sentence. Similarly 'your' and 'you're' are two different words but on many occasions we use them in each other place without noticing. A grammar checker's job is to make sure that your copy is free from similar errors.
An error free copy makes it an easy read to the readers and they enjoy the piece. For a writer, it is necessary that their readers enjoy his or her piece. After all, a writer puts in effort by researching, editing and writing their thoughts down. So, never let your grammar errors spoil the fun of a reader. Run your copy to the grammar check once.