The process of repaying a morgage is usually quite a long-term affair, often taking several decades, but its terms are tentatively decided from the time that the initial agreement is signed.

Of course, most morgages do offer some flexibility. Morgage rates do gradually change over time, and rates that might seem fair at one time could be utterly ridiculous a decade later.

This is why the whole concept of morgage refinancing came about. This makes it possible for debitors to get new morgage quotes, and establish new terms every few years, if they so desire.