I don't think I know if a T is a good fit and there isn't really any clearcut way to test it even from longer term experience, IMO, the way it becomes clear whether an employer or other work relationship is a good fit. The latter can be evaluated based on producitivity, quality of product, motivation to do the work, satisfaction with process and outcome etc. Or a doctor/medical treatment, based on improvement in health. I think therapy and the competence/effectiveness of a T is much more blurry and hard to define whether it is working well, let alone whether it has the potential of becoming productive in a future, based on little experience.

It is much easier for me to tell/predict when a T is not a good fit for me, based on multiple layers of dissonance, that are views are too radically diferent or clashing, that we have too different communication, thinking and emotional styles. But even then, I actually chose one of these Ts to work with for about a year and even went back for a few sessions after a long break and another T, just to find out again, of confirm, that we really are not a compatible combination and it might actually become toxic on both ends if continued. Yet, I feel that I have learned from this obvious incompatible experience and don't feel it was entirely wasting my time and money. I have learned quite vividly what sorts of things rub me in the wrong way, trigger me into destructive behaviors, compromise my mental balance, etc. Not a pleasant experience but not totally useless either.

The T that I thought was a very good fit from start... that was really just based on a strong sense of familiarity and a miriad of similarities (some obviously real, others more just perceived/projected) between us. It was a strong transference reaction on my end even before really starting with him, just based on little info. We had an isntant good connection and I do believe we would never run out of things to discuss. But this situation, this way of connecting, for me, is how I tend to choose friends, and it usually works well that way, in a relationship of equal and balanced roles. With the T, it was certainly very pleasant, but to what extent it helped me to advance with my goals is pretty obscure. I have certainly made lots of progressive steps forward since meeting this T, but it's not like I have not been doing lots of other things as well to make changes. What's nice about the relationship with this T is that it's always positive and we can insipre each-other simply just based on the vibe and mutual engagement when we interact. So is this a good fit? Yes, but not in a sense that he provides guidance or solutions to my emotional challenges.

So based on what I have learned from my T experiences so far, it is really not that important to try to predict whether it is a good fit or not because that question is too complex and can have many layers and angles. More that I feel I have an interest in the T and what they are doing, whether positive or negative. Why am I interested at all? Use that motivation and see where it leads and work with the lessons, try to make it to work for me, to get any sort of benefit out of it that I find worthwhile. Negative experiences and dissonance can also be very beneficial given that we don't get stuck in them beyond what is constructive. I think what I would rule out is a T that seems completely neutral for me, does not spark any sort of curiosity, and I just feel indifferent about them. In that case, it would really be paying for nothing probably.