For the principle of contribution to apply, which factor is typically NOT required?

The principle of contribution is essential in insurance when multiple policies cover the same risk. For this principle to apply, it’s crucial that the insurances involved have some commonality in terms of coverage, subject matter, or insurable interest.

In practice, option D, stating that both insurers' policies have to be identical, is not a requirement for the principle of contribution to take effect. It is sufficient for the policies to cover the same subject matter and have a common insurable interest, even if the terms and conditions of those policies differ. The purpose of the principle of contribution is to ensure that the insured does not profit from the loss by claiming the full value from multiple insurers, helping maintain fairness in the insurance system.

Because of this flexibility, it is possible for policies to vary in coverage while still fulfilling the conditions necessary for contribution. Hence, the requirement for policies to be identical is not necessary, making option D the correct choice.