@red61544While this can apply to the majority of authors, there are few authors around here that are their own editors and they do a decent job.
I don't have any editors (as you can tell from the quality of my work), but I've found a couple of ways to make my text decent enough that I don't get a 2 for score.
Other than the spellchecker and grammar checker, these days, having your computer read your text out loud for you is available to almost everbody and is a great way to find things that sound odd. Also, the one trick that I do is to read the work sentence by sentence from the end of the story to the beginning. It forces one to focus on the sentence and makes sure you don't have missing words or repeated words or homonyms, and definitely helps with long sentences.
But yes, in general, everybody benefits from a second and third set of eyes to look over the text before posting it for general consumption.