Since the tests aren't really scientific, and even ones administered by a professional can be wrong, it's probably good to get a consensus over a wide period time, since even your answers can be influenced by the way you're feeling about yourself at any given time.
Yes, I agree. And this is exactly why I have a bit of a problem with mbti.
It's all about how you perceive yourself when you're taking a test.
In my early 20's, I always tested as INTJ (the humanmetrics test, as well as a few others), and I must admit I related to the type descriptions. I didn't see myself as an NF at all during that time.
I don't relate to the NT temperament anymore. But I think it does raise an interesting question -- was I more deluded about myself then, or am I moreso now? How does one decide?
Personally I don't think it's a self-awareness issue, just a matter of growth, maturity, and gaining more life experience. And, I'm starting to realize there aren't any positive ramifications as far as self-growth goes for me to be able to assign myself to a certain type -- because at this point, I don't think it really matters. I'm still Me, whatever type that is. I think mbti is more useful for other people who wish to categorize me a certain way, and for myself to categorize others. Kinda a hobby. And certainly there ARE noticeable ways you can categorize others, and behavioral patterns - so the concept is a natural one.
I think with mbti though, it's easy to shift our whole self-perception around a description, and explain our tendencies/behaviors based on that description. We explain ourselves based on how we're 'supposed' to be acting, based on our description and type theory, vs. how we might actually BE. Perhaps throwing aside or not mentioning things about ourselves that don't really line up with theory. Fitting ourselves to a theory, rather than assessing the theory itself.