you can’t teach an old dog new tricks

(proverb) a person cannot change who they are, a person cannot change their identity

Example Sentences:

Son: I want dad to go skydiving with me.
Mom: Why?
Son: It is fun, and I want him to experience something new.
Mom: Oh, son, you can’t teach an old dog new tricks. Your father has never gone skydiving before. He’s not going to start now!

Similar idioms:

1. a leopard can’t change its spots
2. change one’s tune
3. on second thought
4. like father, like son
5. got a screw loose
6. beauty is only skin deep
7. believe in
8. every dog has its day
9. take a rain check
10. not all there
11. change of heart
12. come through for someone
13. no hard feelings
14. get through
15. work like a dog