When people start out editing as new users and their edits go to the wait list to be approved, they are asked not to do minor edits.
I feel that is a good basic rule. But there are exceptions.
Sometimes a small edit can change a lot.
I personally will edit when the name of a city, country or area has been spelled wrong or clearly in a language other than English, to make finding questions easier.
Changing the whole post from one version of English to an other is not acceptable, but changing some words to get all the words into the same version of English is acceptable.
Or sometimes I edit small edits to get a question to the top so it gets to be seen again.
Editing out personal style is a No No in my view. We are a site with a very diverse community, let that show in the questions, as long as the words used are real words and the language is understandable for people from other English speaking areas and for people who have learned English as a second language.
Something I am against is people doing serial edits, 10 in a series is about the maximum I am happy with and that can be repeated a few times.
Sometimes it may be needed to edit more, in that case I feel it is important to discuss it in chat and wait for an outcome of that discussion before starting the editing.