I am a very messy writer, and getting worse with age as arthritis kicks in and cripples my fingers. (One of these days I am going to have to change to speech-to-writing technology.)

Because I am  not a good copy editor, I see what I think I wrote, not what I actually wrote. And the only way I can get away from that habit is to read my MS aloud. It slows me down a enables me to see all the mistakes — and I am always horrified by how many there are.

Missing words…
Muddled homonyms because I am hearing the words in my head as I type rather than thinking….
Typing “that” instead of “than”, and a whole stack of other similar one-letter-wrong words which are not really conventional typos but rather fingers going into authomatic mode when it’s NOT wanted…
Extraneous words that I thought I had deleted still there…
Not closing the speech quotes…

And so it goes on. And on and on and on.

But there are others, even worse:
Referring to a character by the wrong name…
Using the same word or phrase repeatedly over and over again…
Using the same phrase over and over again. They exchanged a glance.
Sigh.

And every now and end there are truly horrendous errors, where someone does something that is impossible within the context of the story. (My beta readers are fabulous at catching these.)

And the only way I find these kind of errors is reading aloud. Try it sometime.