It makes sense to write a will and to leave written instructions.
Many years ago, the nephew of a friend committed suicide. He had left everything to his pregnant girlfriend, but because he had only done so via a suicide note and hadn't left a proper will, she got nothing. His parents, who had been part of the cause of his suicide, and who hated the girlfriend, got everything and she was left with nothing.
Needless to say the boy's uncle (said friend) immediately got a will made out to ensure that his common-law wife wouldn't be left in the same position.