The length of time you should fix your mortgage for depends on a number of factors, including your personal circumstances. If you have a stable job and income, you may want to fix your mortgage for a longer period of time, such as five years or ten years. This will give you certainty about your monthly payments. However, if your job or income is less stable, you may want to fix your mortgage for a shorter period of time, such as two years or three years. This will give you more flexibility if your circumstances change.