I regularly encounter people on online MBTI groups who state that their personality type has changed over time. This is incorrect, as per MBTI theory, but there are explanations why those people perceive their type to have changed.
As I understand it, MBTI personality type (defined by preferred/ideal cognitive functions) is static from the age where we create our sense of self; ~3-4 years old. What actually changes is the person’s behavior, and MBTI explains that through the progressive maturity of cognitive functions.
As we grow older and more experienced, we become more capable of using less preferred functions in support of the dominant. That can ‘feel’ like a major shift in how we operate, but isn’t actually a shift in order of our functional stack.
Likewise, there may be traumas or other external influences that cause us to suppress or regress our useage of different functions. This can also effect a tangible sense of personality change – but, nonetheless, our ideal functional stack order remains constant.
It’s also noteworthy that how we “identify” is highly liable to change. Our self-identity is a product of the ego and the creation of persona. Self-identity doesn’t have to reflect reality and can be healthy or unhealthy depending on a myriad of conscious and subconscious factors and influences.
The real benefit of MBTI personality typing isn’t in explaining who we are today, or were yesterday – but rather it provides us with a cognitive structure explaining who we SHOULD always have been. It is this personal ‘benchmark’ that allows us to identify where we have deviated from the ideal, and why we have experienced failures as a result of it. Understanding that we deviate from a natural, inherent ideal is the first step in remediating ourselves and self-developing in ways that will bring more success and ease to every aspect of our lives.