Your mortgage amortization years are divided into 1-2-3-4-5 and even 10 years term at a time, enabling your lender to adjust interest rate to current market conditions and or simply reclaim the loan from you for various reasons, what they do not even have to disclose to you. Make sure you are using a mortgagebroker to shop the lenders for best rates and products along with the most suitable term custom fitted to your needs and not of the lenders.
You should or have your broker time to time check the rates and refinance in case your broker can provide you a calculation you save money for the long term and or your needs have changed and need another product to reflect same. Nothing wrong with to cross the floor to another lender to save money, it is your money.
You will never find cheaper money than mortgage money. As it is secured with the equity in your home you are able to borrow the funds needed against that equity. Your equity is the value between the appraised value and the existing mortgage amount.