For my work stuff with magazines, I almost always leave it a few days between writing, editing, proof reading, editing again, proof reading again, until one day, I read it and cannot see anything that needs fixing or improving.

On Medium, I'm less pedantic. Partly because I can edit later, partly because I'm impatient, and partly because no one's paying me £200 to get it perfect. Also, my Medium stories are generally shorter, so they require less editing anyway.