Don’t use quotation marks when nothing is being quoted

Don’t use quotation marks when nothing is being quoted. If you want to highlight a specific part of the text, use italics or bold.

• Any orders ‘over £500’ will receive a 10% discount.
  Any orders over £500 will receive a 10% discount.
  Any orders over £500 will receive a 10% discount.
• The dog was barking all day.