  Several hairy black hole solutions are known to violate the original version
of the celebrated no-hair conjecture. This prompted the development of a new
theorem that establishes a universal lower bound on the extension of hairs
outside any $4$-dimensional black hole solutions of general relativity. Our
work presents a novel generalization of this ``no-short hair'' theorem, which
notably does not use gravitational field equations and is valid for arbitrary
spacetime dimensions ($D \geq 4$). Consequently, irrespective of the underlying
theory of gravity, the ``hairosphere'' must extend to the innermost light ring
of the black hole spacetime. Various possible observational implications of
this intriguing theorem are discussed, and other useful consequences are
explored.
