The length of your term can affect your interest rate, mortgage features, and how soon you will need to renew.
A shorter term brings you back to renewal sooner. This may be useful if you expect your plans to change, but it also means you will be exposed to the rates available at that earlier renewal.
A longer term keeps the mortgage agreement in place for longer. This may provide more payment or rate certainty, depending on the mortgage, but the cost of breaking the agreement early may also be an important consideration.
The right term depends on more than the interest rate. Your plans, need for flexibility, prepayment options, and possible penalties all matter.