How important is email accuracy?

In my job as a sub editor I come across so many basic errors in grammar and the use of unnecessary words.
These are exhibited by junior writers with no more than six months of cub training to senior writers and even contributors who are academics in their respective fields.
These are just a few of the most common.
Today I’d like to share these word pairs that always confuse new writers. Not to sound arrogant there are plenty words in the English language that I need to check on for correct usage, despite considering myself an English language professional.
I have selected these five word pairs so that you can easily increase your word power.