Renewal explained
A renewal happens when your mortgage term reaches its maturity date but a balance remains. Since a typical 25-year amortization is broken into shorter terms, often five years, you must renew the mortgage each time a term ends to continue paying it down. At renewal you agree on a new rate and term for the outstanding balance, either with your current lender or by switching to another.
Renewing with your existing lender is usually simple, sometimes requiring nothing more than signing the offer. But the first rate a lender offers at renewal is often not its best. Shopping around, or switching lenders, can secure a lower rate, and switching does not normally trigger a prepayment penalty because you are at the end of the term, though a new lender may require you to re-qualify.