10.1 The period during which the insurer is liable to indemnify the assured is determined by construction of the terms of the policy. However, this naturally requires elaboration. The cover provided by all insurance contracts endures for a period of time. Even so, there are different ways in which this period can be calculated; and these calculations may be made either on the formation of the contract or subsequently. The Marine Insurance Act 1906, section 25(1) identifies the two principal methods of calculation as follows: