I just learned that my MBTI personality type is different than it was a couple of years ago. I was INFP – A and now I am INTP – T. I find all of this fascinating and I had no idea it could change over time.
In theory, according to the developers, it cannot change. As you get older, you just gravitate toward some aspects of your personality more than others, so it feels like a change. Also, taking the online tests are less accurate. But it cost a lot to take the official one with a professional, and you can't buy them because the companies that sell them require
In my opinion though, it can change. I lean more toward cognitive-behavioral theory, which has the philosophy that our personalities are continually changing all the time, with every new experience and every time we challenge a thought process.