Q: How do I know if I need an editor?
A: No question finds its way to our desks more often than this one. Luckily, the answer is straightforward and simple.
If you write, you need an editor.
That being said, you don't always need a professional editor; it depends on your publishing goals. If you have a term paper for Economics 101, you may want to find an English major and pay them $10 to skim your paper. It'll save you a few bucks and you probably won't fail your class for a dangling participle here and there.
If your novel is full of errors like that, however, you stand a good chance of receiving that "thanks, but no thanks" letter. There's a reason why even blockbuster writers have editors.
As a general rule, your need for an editor is directly proportional to the number of potential readers you are trying to reach.
Q: Why don't you have a standard rate for each of your services? Why is there a range on each service?
A: Every project that comes our way is unique, and even if we employ the same service, some manuscripts are going to require more technical knowledge than others.
Let's say Mr. Fantasy Writer just finished a draft of his latest masterpiece--The Ice Dragon of Everlore--and wants us to perform a quick copyedit before submitting to publishers. The next day, Ms. Master Degree is ready to go before the doctorate board for a review of her dissertation and would like to have a copyedit done to ensure that grammar doesn't hold her back.
Although both clients want the same service performed--copyediting--the dissertation is going to require more editorial steps than the novel. The editor will need to fact check the dissertation, ensure that the document is formatted to the proper style (MLA, APA, Chicago, etc.), and be on the look out for structural inconsistencies that break apart the argument being put forth: issues that fiction need not worry too much about.
Essentially, the more technical knowledge required of the editor, the higher the rate for the service.