Editing tools, if you use them correctly, can help writers identify certain areas in which they can improve. While I don't suggest depending on these tools, they definitely don't hurt. The key is to know why you're agreeing with whatever the tool says and only making the changes you agree with. Never assume the tool is right. Many times, it may not be. Then, if the change is something you've had to do more than once, add it to your style guide so you can be consistent with your flaws and attack them early on in future works.
