Dic: [set] be set in your ways

▶ If you say that someone is set in their ways, you are being critical of the fact that they have fixed habits and ideas which they will not easily change, even though they may be old-fashioned.

▶ be set in your ways: to have habits or opinions that you have had for a long time and that you do not want to change

▶ set: (usually postpositive) rigid or inflexible

▶ [OPINIONS/HABITS ETC] not likely to change

▶ (4) not willing to change your opinion or way of doing things. (4a) used about people's ideas or behavior:

• People had very set ideas about how to bring up children.
• Mark was 65 and rather set in his ways (=habits) .
• be set in your ways: He's old and stubborn and set in his ways.
• She has very set ideas about how to raise children.

.... COBUILD, OALD, COLLINS, LDOCE, MacMillian