Is always effective; always does what's desired or intended. If none of these things resolve the issue, turning your computer on and off again never fails. I'm telling you, drink this—it never fails to get rid of a hangover.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
something never fails
a particular thing always works. My old folk remedy for hiccups never fails.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.