serve a, his, its, etc. purpose
serve (one's) purpose
To fit or satisfy one's requirements; to be useful for or fit to achieve one's aim, goal, or purpose. Well, it isn't a very pretty car, but it should serve our purpose just fine. Child: "But Mom, I want a smartphone!" Mother: "Nonsense, the cell phone you already have serves your purpose just fine."
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
serve a, his, its, etc. ˈpurpose,
serve the ˈpurpose (of doing something)(British English also serve his, its, etc. ˈturn) be useful for a particular purpose or period of time; be good or useful enough for somebody: It’s not a very good radio, but it serves its purpose. ♢ He used his friends and then abandoned them when they had served their turn.
Farlex Partner Idioms Dictionary © Farlex 2017