I do use Hanon and have done for 36 years.
I know i am going to be shot down for this but mostly i play a chord of g# b d f g#. I then play one note at a time for about 50 repetitions whilst keeping the others still.
How can you? I think I have to shoot you down

My own piano teacher who is an astounding concert pianist with a set of fingers as good as anyone (he has played all of the Horowitz transcriptions live), does this every day and it is the only exercise he does.
This must serve as the most extreme example for the delusional power of exercises. I am sure you have good technique, and I am also sure you don't attribute it to this exercise, so you understand that I don't mean to offend. But for the sake of the young ones who believe in exercises, let me point out two things:
First, you are doing an exercise that is very silly. You play one chord with certain variations. This touches on a miniscule portion of what constitutes piano playing. So, your exercise doesn't cover any real ground.
Second, you are invoking an authority, saying that your teacher does only this one exercise, and he plays fabulously. Surely, your teacher didn't get his fabulous technique from this one exercise. However, it would seem that one should attribute his fabulous technique to this single exercise, because it's the only one he is doing. What it should tell you is that he doesn't have to do any other exercises, because he already has fabulous technique, and as I said above, once a technique is mastered, one doesn't have to practice it anymore. Merely playing repertoire is sufficient to maintain it.
So, your exercise isn't really an excercise aimed at advancing technique. It is there to make you feel good, to give you a sense of security, like "I've done my exercise, nothing can go wrong now". It is superstition! If your teacher told you that, every morning, he stands on his left foot and jumps up and down for five minutes while scratching his left ear using his right hand, and that's the only exercise he does, you would probably be doing the same. And you would say "everybody, go jump up and down, because it works for my teacher."
Again, I am sure you realize all this, and everybody can see the silliness in this particular, extreme example. What many people can't, however, is to recognize the same silliness in more complicated settings. For example, someone who plays through Hanon every day may not feel silly at all and may also say "my teacher is doing this, and he is fabulous". Yet, it is still as silly. It becomes even harder to recognize for those who say "I play Czerny and Pischna, and Rachmaninoff said it's a good thing." What they don't tell you is all the other stuff that helped them gain excellent technique. They play through a lot of repertoire and prepare it for performances. It is hard, or even impossible, to pinpoint which of the thousands of movements throughout a day actually did advance their technique. But it is easy to point to Hanon, or Czerny, or Pischna, because those are well-defined entities, and they are furthermore designed to advance technique. So, advances in technique are attributed to those exercises. Is it really true? I think most of it is superstition (there might perhaps even be some self-cheating: "I have spent two hours on these stupid exercises. I'd hate to believe that I have wasted my time. Therefore, I simply claim that they have helped me advance my technique.") In addition to this component, there is probably indeed a small amount of improvement in the technique that people gain from these exercises. But I am personally convinced that the same, and even more, improvement can be gained from playing repertoire. And you might again be the perfect example for this type of approach: the exercise you are doing is certainly not responsible for your technical abilities, so it must be your attentive playing through regular repertoire. QED

Thanks for this very illuminating example

(I am beginning to think you are pulling our legs and only wrote this to reveal the silliness of exercises by makig up this extreme example...)