Correct grammar, punctuation and spelling are key in written communications. The reader will form an opinion of you, the author, based on both the content and presentation, and errors are likely to lead them to form a negative impression.
If you are unconvinced about the importance of accurate writing, think of the clues we use to identify spam emails, “phishing” websites, and counterfeit products: poor grammar and spelling.
Similarly, some employers state publicly that any CV or résumé containing spelling or grammatical mistakes will be rejected immediately, whilst a BBC news article quotes research that calculates spelling mistakes cost online businesses “millions” in lost sales.
Checking for poor writing and spelling mistakes should be seen as a courtesy to your readers since it can take them much longer to understand the messages in your writing if they have to think and re-read text to decipher these.
All written communications should therefore be re-read before sending to print, or hitting the send button in the case of emails, as it is likely that there will be errors. Do not assume that spelling and grammar checkers will identify all mistakes as many incorrect words can indeed be spelt correctly (for example, when “their” is used instead of “there” or “principle” instead of “principal”) or entire words may be missing. If at all possible, take a break before re-reading and checking your writing, as you are more likely to notice problems when you read it fresh.