Be wise and observe the terms and amortization payments schedule in your mortgage to see how much you can save with your educated decision, rather than just the standard or automatic mortgage renewal from your lender.
When you choose to renew on a yearly basis, you are also choosing to be subject to the rate that the lender will determine around 1 month before the renewal following a letter from the lender recalling the mortgage (which adds to the stress)
When you choose to renew your mortgage automatic you will also start a new term to which you need to agree, and when you start a new term, you will also start a new amortization period in which you can see that your payments will be applying more to the interest than to the principal, extending the length of time for you to liquidate your mortgage for good. This is also translated in a much expensive borrowing, costing you seriously more at the end. It is not wise in most cases to renews automatically, and why do it when you can have your mortgage assessment done for free?