For starters, it’s always good to get a second opinion and have someone look at our writing who is not emotionally attached to it. Although we don’t like to admit it, we do become emotionally attached to what we write. A second opinion like this can also often open up new ideas and avenues for the characters and plot that you might not have thought about.
Secondly, although we can all self-edit to a certain degree, we quickly become blind to the errors in our own work. We editors are probably the worst culprits at this. I know I am, I’ve made many changes to my website because of errors I’ve made. The thing is when they are pointed out they are so glaringly obvious.
Editing isn’t cheap. Contrary to popular myth we don’t do it for love. We do it to try and earn a crust. It’s also very time-consuming. A full substantive and copy edit of a novel cannot be done in a few days, it takes time and energy on the part of the editor. In my experience, it can take up to three months to do a satisfactory professional job. My advice, therefore, is to budget for at least £500 upwards for editing. A lot of money, but hopefully a wise investment. Although in saying this, I’m more than happy to negotiate a rate that’s more affordable (within reason).