It is odd thing that a meditation technique needs to be matched to a person’s brain, wherever that person’s brain is at the time, in order to work.

There are dozens of meditation techniques. Each of them works of something like 5%-30% of the population. There’s currently no way of figuring whether a technique will work for you without trying it.

It’s a little worse than that, in that whether a technique works for you may change over time. A technique may work for a while, stop working for a time while you do some other technique, and then start working again. It’s like a technique has something to teach your brain in it’s current configuration, and when it finishes that, it stops working.

In TMI, and indeed any practice, you should be seeing steady progress. Every 3rd meditation or so, it should feel different – generally your attention should be more stable. If you are not progressing, you are at least stuck, and possibly mismatched. If you are stuck, you should stop, try to identify the problem yourself, or consult a teacher. If your meditation seems pleasant or neutral but nothing changes, you’re stuck.

The going-to-the-gym analogies work here. If you are lifting a particular weight a particular number of times, after a while it might not induce any more progress. It’s time to do something else.

First try to get yourself unstuck. Elsewhere on this site I have advice about that.

If you are mismatched and want to completely try something else, the Fundamental Wellbeing Foundation https://fundamentalwellbeing.foundation is an interesting resource. They providing free various sampler programs that let you try out different techniques. I have not used them, but I did go through one of the predecessor courses (“45 Days”), developed by Jeffery Martin.