Contract of affreightment often expressly provides for compliance with some specific conditions for notice of readiness to be valid. It can be required, for example, that the vessel must be entered in the customs' house before notice was given or free pratique has to be obtained or that the notice to be given within stipulated time window . In such cases the commencement of laytime begins only when the event stipulated in the charter occurs, the giving of the requisite valid notice and its validity depends on the conditions stipulated in the charterparty for its giving being met .

Alternatively, the parties are free to contract out any specific or standard requirements which, if not met, would have made notice of readiness invalid . The purpose of such fine-tuning is to relocate between the parties liabilities for delays in port, but extensive litigation on this subject demonstrate all the numerous problems of achieving an unambiguous result.