Some terms are implied depending on the circumstances of the job. Some exist because they are so obvious that they go without saying, while others may be said to exist because, although they were not expressly raised at the time the contract was made, it is certain that they would have been agreed on if they had been raised. In some trades there are terms that are implied as a matter of custom, but these must be well known and accepted before they will be recognised by the courts. An example of an implied term is where an employer will pay an employee for time spent in washing or cleaning up if the work is dirty.