be set in your ways

be set in (one's) ways

To be habituated to one's routine or usual behavior, often to the point of being unwilling to change any aspect of it. Grandma will never retire—she's been a teacher for 50 years and is totally set in her ways. You'll never convince him to change, he's too set in his ways now.
See also: set, way
Farlex Dictionary of Idioms.

be ˌset in your ˈways

be unable or unwilling to change your behaviour, habits or ideas, usually because you are old: He’s too set in his ways now to think about a career change.
See also: set, way
Farlex Partner Idioms Dictionary
See also:
  • be set in (one's) ways
  • set in one's ways, be
  • fixed in (one's) ways
  • be young at heart
  • be, stay, etc. young at heart
  • get used to (someone or something)
  • have (one's) heart in the right place
  • habituate
  • habituate (someone) to (something)
  • habituate to