|I hasten to mention that this is not what my CP looks like :)|
A Critique Partner, Beta-Reader, Proof-Reader, whatever title you want to give them, they are an essential part of a writer's entourage (of course I use that word very loosely, I have no entourage unless you count two kids and a dog - it's just a flash word and I like it).
What do they do? They take your manuscript and look at it with fresh eyes. Let's face it, how many times do you actually read your own manuscript? Too many times to count.. until the words all blend into one big black splodge, like a weird Rorshach test.
They weed out our appalling grammar, sentence construction and gaping plot holes. Not to mention the words we love to make up. What? That's just me? *blushes and moves on*
But there is something else they do. They help you polish your manuscript and although the saying is that it's not possible to polish a turd, I beg to differ. They don't just tell you you're crap or make a load of suggestions or comments for the sake of it. They want you to be successful. They thrive on your achievement and want you to be the best you can be.
So, if there are more track-changes on your manuscript than there is on the London Underground, you may well sit with your mouth hanging open, and the vague thought of "What the hell does she mean? I know how to write!" but then you have a moment of clarity like a light bulb illuminating above your noggin. She's right. And you polish your turd and your CP comes back to you jumping up and down and doing the Snoopy dance because not only have you run with some of her suggestions, you've managed to add another two thousand words in the process and delved deeper into the character - which is what your reader wants - and what will ultimately lead to your success.
If, however, you think you can do without one... you are sadly mistaken... because I couldn't do without mine. Not only is she my CP - she is one of my closest friends and I would be lost both without her fresh eyes and ideas and her love and support.