The other day a client came in to have her Estate Plan prepared. She did not have an heir. Her husband, siblings and only child predeceased her. Her father was living ( in his 90's). She wanted to know if she really needed Estate Documents as she did not care what happened to her assets once she passed. We discussed her legacy and what if any Charities or Colleges she would like to benefit. She had come up with a few Charities.
So even if you have heirs and you desire to leave nothing to, or have no heir think about charities or others, you may desire to benefit by leaving your assets to a good charitable type organization.