The anniversary date is the renewal date of the policy. In general, the term of a policy is one year from the effective date of the policy.
Exception: Health insurance policies:
The anniversary date of a Health insurance policy is always set for the 1st of January. This means that if you sign up for a policy on 21 April 2018, you are committed until 1 January 2020, the policy renewal date.
A premium due notice is sent to you beforehand to inform you that your policy is expiring and to invite you to pay the premium for renewal.