call it a day
US /kɔl ɪt ə deɪ/
UK /kɔl ɪt ə deɪ/

1.
to decide to stop working on something, either for the rest of the day or permanently
:
•
It's getting late, let's call it a day and finish this tomorrow.
•
After working for ten hours, she decided to call it a day.