I already mentioned this fairly recently, but it’s important enough to bear repeating. Understand there are several types of editors. Proofreaders look for typos. Copy editors look at punctuation and grammar. Line editors look at sentence structure and flow. Content editors look at plot & characterizations.

If you’re lucky enough to have a first-rate publisher, they are likely to provide all of these. If you’re an indie author, then it’s essential for you to understand these different roles. Just because you can come up with a clever story doesn’t mean it will be worth reading unless you can convey it effectively. The skills these types of editors represent can help make sure you do.

Of course it’s going to cost you. Thus, it will serve you well to educate yourself and become the best possible writer so as to minimize the help you require.

If you want more detail regarding the types of editors you can find it here.