horses for courses
The phrase stems from the fact that a racehorse performs best on a racecourse to which it is specifically suited.
- (idiomatic) A person suited for one job may not be suited for another job.
- (idiomatic) The practice of choosing the best person for a particular job.
- The chiasmus "courses for horses" is less used.
- The term is widely used in the foreign-language translation industry, where a translator is selected for a job not solely based on his or her fluency in the language, but also based on knowledge of the subject matter.