As you consider a yoga teacher training and what kind of teacher you aspire to become, I invite you to consider what makes an excellent yoga teacher? Instructors come with varying degrees of knowledge and direct experience. Some simply make stuff up (think goat or bar yoga) while others are steeped in tradition and personal revelation.
Many teacher trainers are relatively new to the practices while others have studied their whole lives. As obvious as it may sound, the depth and history of a lead instructor has a big impact on the final outcome of your training.
The way I see it, teacher trainers ought to be a dedicated student for at least a decade before they offer a YTT. What’s more I suggest that they have at least 5 years of teaching under their belt.
As a rule of thumb, a teacher should to have 10 times the knowledge as those whom they teach. This may seem like a lot and I think it is a reasonable standard/expectation, particularly if you want to accelerate and deepen growth. In many ways, this is the point of a yoga teacher training. Teachers with that level of training and experience exist though they are less common.
Consider, where did the teacher study and under whom?
If you read trainers bios they may reference a long list of everyone they studied with. It’s questionable how much time they may have spent with any of these teachers. Maybe it was just a one time workshop? Good enough, put them on the list too.
I think that depth is more important than breadth. Tradition is sometimes shunned as archaic or impractical, which may be partially true. And we should consider that with heritage often comes depth and wisdom.
It is better to dig one deep well than many shallow ones that never strike water. As a loose guideline, I suggest that students and teachers have no more than two primary influences and study with those influences for a decade or longer.
Consider what your standards are and what makes an excellent yoga teacher before you embark on a particular training.