always effective► reliable · The system is new, but so far it seems to be reliable.a reliable way/method etc of doing something · Eating sensibly and taking regular exercise is a fairly reliable method of losing weight.· In Africa, cellular phones are often the only reliable way of communicating.
► surefire certain to be effective or successful: · Thursday night's line-up includes such surefire attractions as 'The Simpsons' and 'Friends'.a surefire way to do something/of doing something: · I know a surefire way to get a car started on a freezing winter morning.a surefire solution to something: · There's no surefire solution to the problem of improving the company's performance.a surefire recipe for success/disaster (=something that is certain to be successful or not successful): · Going on holiday with my parents would be a surefire recipe for disaster.
► foolproof a method, system, or plan that is foolproof is always effective, because it is simple to understand and operate, and cannot go wrong: · I thought this method was foolproof until four customer orders went missing.· Each article goes through a foolproof system of checking which ensures that there are no mistakes in the final text.a foolproof way to do something/of doing something: · There's no foolproof way to judge whether someone is the right person for the job.
► infallible a method or system that is infallible always produces the right result and never goes wrong: · Banks claim their cash-dispensing computers are infallible.an infallible way to do something/of doing something: · There is no infallible way of predicting exactly what the weather will be like.
► never fails/can't fail/works every time spoken use this to tell someone that a method is always effective, especially when you have used it successfully before: · It's a very simple technique, but it never fails.· If I'm having trouble sleeping, having a hot bath at night works every time.· You should try this recipe. It's so easy that you can't fail.