Headscratchers / Body Double

• How did Sam know that his wife wouldn't be home during Holly Body's dance sessions?
  • Well, he was her husband, and therefore had access to her schedule. We don't know what Gloria did for living - given it's Hollywood, maybe she worked in the film industry? Or some other job where working evening hours is common? She was obviously wealthy; if she didn't work, perhaps she had some kind of volunteer committee to go to in the evenings?