The phrase "old habits" refers to long-established patterns or behaviors that someone has developed over time. These are actions, thoughts, and routines that a person may have done for many years without realizing it, often because they seem natural or automatic. The term can also imply that these habits might not be beneficial or productive in the present day, but nevertheless remain ingrained in someone's behavior due to their familiarity and comfort. In essence, "old habits" represent a person's past ways of thinking and doing things, which may no longer serve them well but are still difficult to break.