break a habit
break a/the habit
To stop doing a routine action or activity. I struggled to break the habit of biting my nails, but getting regular manicures helped.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
break a habitand break the habit; break one's habit
to end a habit. I was not able to break the habit of snoring. It's hard to break a habit that you have had for a long time.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.