I think that we all have those tried and true bits in our collection while others we just steer clear of. Are there any bits that work like magic for your horse?
Apollo's magical bit is the Happy Mouth Shaped Mullen Mouth Loose Ring. He uses a 6" and I recently bought a 5.25" for my young horses.
I stumbled into using this bit by chance. I forgot my bridle one night when I had a lesson and had to borrow a bridle from my coach. Her biggest bridle had this bit on it so I used it. And Apollo was more respectful and responsive to it than his previous d-ring snaffle. So I stuck with it!