This is ultimately your decision but the greater the length of time, the higher the premium will be. It is better, however, to apply when you’re young. Personal Life insurance is taken out to protect the financial security of your dependants. For this reason the most common duration of a Personal Life Insurance policy is between 20 and 25 years or until your dependants have completed full-time education. For mortgage-related Life Insurance, it must be for the term of the mortgage.