Once you have bought a health insurance policy you need to be aware of the duration of the policy so that same can be renewed on time.Health insurance policies are valid for a period of 1, 2 or 3 years.
Renewing the policy is very important to get the continuity benefits. The continuity benefits are
1) Waiver of the 30 day waiting period: You can claim from day 1 for renewal policies for any disease
2) Reduction in the specific Disease wait period: Depends on the initial wait period clause in your plan. This reduces by the number of years of continuous renewals.
3) Reduction in waiting period of pre existing diseases: Again this will depend on the plan clause and the pre existing disease waiting period will reduce by number of continuous renewals
4)Another advantage of renewals is that all diseases that have occurred during the policy lyear will have to be covered by the insurance company without applying any pre conditions like ncreased premiums or additional waiting periods.
As per IRDA all insurance companies have to provide life long renewal and cannot refuse same on any grounds if you have requested for it in time. Usually IRDA also mandates that insurance companies have to allow renewal till 30 days from polc expiry date.

So it is very important that you keep track of the renewal date and do it on time.