once and for all
Meaning:
If you do something once and for all, you do it in a way that’s final and it means you’ll never have to do it again.
->For example:
-Jim said he’s decided once and for all that he’s going to stay single and never get married again.
-I was tired of getting new glasses every few years so I decided to solve my eyesight problem once and for all and have laser surgery.
