How do you know if you have a long, short, or regular/average neck length? I see many posts about the ability to wear this or that collar due to neck length. I've read Inside Out Style Blog that talks about proportions but doesn't specifically address neck length. I have looked all over the internet but maybe I'm not "Googling" the right thing. Mostly, I've found to just "eyeball it". But for those of us that don't know what to "eye" is there an easy way to tell? Visuals would be helpful.