They don't fall out if I sit still, don't exhibit any strong emotions, let them lie in my ear naturally, and feel at ease wearing them for two to three hours. They need to be regularly adjusted if I move around a lot (this is not exercise), not because they fall out but rather because their position greatly affects the sound. And as soon as you begin to smile, they start to travel up and out from the ear canal, almost falling out, and the sound becomes "empty" (as if coming from a distance).
TheSee full review