It's not hard at all. If your going to do it yourself and not pay someone to do it, then it's really pretty simple. If the helmet is not painted, just the factory plastic color, then you can use a can of Krylon, but it may take a couple of coats. If your helmet was painted then I would primer it first, then paint it the new color. I would also do this in a place that is shielded from the wind for the best results, but then air it out unless you like the buzz.(ha ha) Sometimes though automotive shops will paint them for you, but I'm not sure how much they charge. Good luck!
Noble County Wolfpack