I had a professor whose mantra is “Words are the tools of our trade.” She would make us repeat this at least once each class. Why am I telling you this? Because, words are important and make a difference. One reason to use a lawyer when preparing your will is that you want certain things done.
If you have more than one person you want to split your belongs to, words matter. For example, equal and equitable have a different meaning. Depending on how you want your belongs split, it matters what word is used.
Working with a lawyer will help make sure that your belongs are distributed in the manner that you want.