I self-edit, largely. Any short works are all me.
That said, I've been working in the technical writing field around 10 years, now. The last 6.5 years, that's been my whole job. I have to self-edit a lot, as tech writing is still rather under-appreciated in IT

But I spent the first couple of years having people tell me that various mistakes had caused major stuff-ups here and there... so I learnt a lot about carefulness
For my longer works, I self-edit, then I get beta-readers to help out. Maisy May is my only experience with this so far - 10 people with various specialities, and boy did they help! Mostly just little things - like "Maisy sends a text message in Chapter 3, and in Chapter 10 her mum gives her her first phone..." or punctuation/typography issues.