I have a collar, but it wasn't given to me by my dominant. He lives too far away. It was given to me by a domme friend because she wanted me to have it. It used to be hers. She's never been my dominant. It was interesting she had a subbie collar. When she gave it to me, she told me she's a switch. So, in a way, it is symbolic, but I'm not sure what it's symbolic of.
The times I wear it are special, like when I'm most submissive, do tasks, or play with him.
I often wear it sitting naked writing a piece from a submissive point of view. It brings out very powerful feelings in me and it is when I'm most creative.