I always avoided wearing it to spar, and in MT we never had to wear it apart from for novice fights, and I only did one of those before moving up to amateur/full. I hate the damned things, I feel like they obscure my periphery vision and just feel awkward. Also I can roll/glance punches off of my head much better without them.
M.O.B.F.O.E. - Money Over Bitches, Fitness Over Everything