When I joined AEPhi, we were "strongly encouraged" to wear our new member pins every day. I think I actually did wear mine every day... We were a colony trying to recruit enough new members to be chartered, so we had to get our name out, and having people ask "Oh, what's that pin you're wearing?" helped.
We were allowed to wear our NM pins while wearing jeans - oddly enough - even though we had ribbons that we could have worn.
When I was pledging my local sorority, we had pledge rings that we were required to wear at all times (except for the 4 S's that dardenr mentioned - I never quite thought of it that way - LOL)