Stick To Meaning

(idiomatic) To persist; to continue (to use, do, etc.)

Example:   I have seen all the fancy electric toothbrushes, but I'm going to stick to the old-fashioned kind.
  If you stick to your studies, you will continue to improve.
2007, Amanda Lamb, Smotherhood: Wickedly Funny Confessions from the Early Years:
  What I get from work makes me a better mother, and what I get from being a mother makes me a better journalist. At least that's my story and I'm sticking to it.
Used other than as an idiom: see stick,‎ to.