It rarely occurred to me: consider doubting your teacher.
I told a student recently, “Always remember that every teacher has a perspective.” It’s important to recognize the perspective and then take what serves you in pursuing your goals.
In my classroom, I value understanding how the music works. But if that’s not important to some of my music students, I’m okay with some eyes glazing over as I discuss quartal harmony! (So long as they don’t disrupt others’ learning.)
In a classical voice lesson, some students might hear that bel canto is the only healthful approach to singing, and be warned away from other vocal techniques. But if you want to be effective at singing pop, jazz, or musical theatre, you’d best not sing that repertoire as if it’s “Già il sole dal gange.” At least, if you want to get the gig!
There are ways to value the lessons you’re learning and respectfully disagree. Indeed, I think that doubting your teacher doesn’t require voicing your doubts to them. Take what you can take from their teaching and explore other ideas outside of their purview.
Good teachers have much to offer, and deserve our respect and appreciation. They don’t deserve to be blithely followed without critical thinking. Including me. Including you.