you can't teach an old dog new tricks

It means that it is very hard to change someones habits

You can't teach an old dog new tricks when they have been used to using a cell phone instead of a smart phone.

7👍 2👎

teach an old dog new tricks

when someone does something for a long time and its hard to teach them new abilities.

you cant teach an old dog new tricks, my uncle never learned how to use his cellphone.