I ensure your text is consistent. What does this mean?

Either . . . or

50 percent or 50%? $20 or USD 20? 12 feet or 12 ft.? Or 12 ft? Or maybe twelve feet?

All these examples are correct—but not within the same text. You should either always use the abbreviation for units of measurement or always spell them out. Where applicable, either always use the respective symbol or always use the word. Either always use a period after the abbreviation or always leave it out.

In short: whenever there is more than one way of writing a word, choose one option and stick with it.

The same holds true for language variants: if a language has more than one variant—e.g., British English and American English or Federal German and Swiss German—decide on one and use it consistently throughout your text. A company should pick one variant as its corporate language and use it consistently for all published texts.

I clean up your text ensuring consistency and, if applicable, observe your corporate language.