If you think that your estate plan just needs to address your assets, it's time to dig a bit deeper. To create an effective plan, you not only need to pass your assets on to your heirs, but you need to do it in a way that minimizes conflict. You want them to have strong family ties for the rest of their lives, after all, and you want to avoid litigation and estate disputes if possible.
People make a lot of mistakes when creating wills and estate plans. Some don't make a will at all. Others forget about tax implications. Still others don't think about the sentimental value of certain items and create conflict between siblings.