There are two ways to refinance: internal refinancing at the same bank, and external refinancing, moving to another bank that pays off the old mortgage.
Internal refinancing
Advantages: - A simpler and faster process. - Usually no need for a new appraisal and registration. - Exempt from the no-notice fee.
Disadvantages: - The bank knows it is hard for you to leave, and will not always give you the best offer.
External refinancing
Advantages: - Real competition: the new bank wants you. - The option to rebuild the whole mix.
Disadvantages: - More bureaucracy: appraisal, registering a new mortgage, insurance. - Additional costs. The cost of refinancing
The trick: use the competition
Banks do not like to lose mortgage clients. Often, when you come to your current bank with a written offer from another bank, the internal offer improves. That way you get the terms of external refinancing with the convenience of internal refinancing.
More: when to refinance.