The personal pronoun "a" should be used before someones name human/animal. The personal "a" is not used when the direct object is not a person or is an animal for which no personal feelings are felt. It should mostly be used before names because it is the correct form of spanish grammer. It also should be usted before personal pronouns such as mi, ti, él, ella, usted, nosotros, nosotras, vosotros, vosotras, ustedes, ellos, and ellas