you can't teach an old dog new tricks
idiomPart ofteach
you can't teach an old dog new tricks — idiom
1. said when someone is too old or set in their ways to learn new skills or change
1.idiom
Definition
said when someone is too old or set in their ways to learn new skills or change their habits
Example
I tried to show my grandfather how to use the phone, but he said you cannot teach an old dog new tricks.