I first got into typology/personality types after seeing ITZY taking the 16personalities test on Youtube. At that point it was just mild interest and I ended up getting ISTP-T on my test.
Fast forward a few months to my discovery of Personality Database in September 2020 where I was introduced to Jung's cognitive functions. That led to me researching typology for the next couple of years until now.
Initially my understanding of the system was rather flawed, but I think that in the last year I have managed to grasp the concepts and found their practical applications in my life. As I researched the cognitive functions I looked into the enneagram as well as some other systems, but the functions and ennea have been of the most use to me. Of course, I will always take typology with a grain of salt. However, what I've found after a while has actually been able to help me, so there are a select few parts of typology I take somewhat seriously.
My experience with these has been quite the rollercoaster. Like I mentioned before, I first typed as an ISTP in my 16p days. After discovering the functions I went from ISTP to ISTJ to a tentative INTJ to a certain and final ENTJ.
Only in August 2022 had I managed to understand the functions and myself to the point where I could accurately type myself. I did some in depth searching, read chapters of Psychological Types, asked as many people as I could, and finally settled on Te-Ni ENTJ.
Overall the cognitive functions have been a useful tool in my life. Noticing the functions in myself and people around me has allowed me to understand people better, which lets me predict them easily and interact with them better. These abilities are massively helpful in a multitude of scenarios.
I've had 2 mistypes with enneagram. Looking back at it I have no idea how I messed up such an obvious thing, but it is what it is. 3w4 so/sp 368 is the conclusion I've come to regarding enneagram, and it has made pretty much my whole childhood make a lot more sense to me in the process.