Time is of greater or lesser importance to the parties in most kinds of contract. It is quite usual for the contracting parties to stipulate for a date for delivery for the sale of goods. Failure to comply with such a stipulation is, obviously, a breach of contract, but whether it is a breach of a condition or a warranty will depend on the intention of the parties. This intention will be assessed by reference to the express terms of the contract and, where appropriate, the nature and circumstances of the contract. A time clause in a mercantile contract is not necessarily a condition. Where a requirement as to timing is essential to the contract, the expression used is that 'time is of the essence'.