Not in my house they don't. But I don't know if that is proper or not.

No, they stand on their own as decorative objects.

no.

I like twigs in mine:).

I put fireplace matches in one of my vases. Everyone seems to comment on it positively.

Here are some vases in my living room - the large one is from Honduras and has a Bavarian cane and some African fishing spears in it (plus a spray of dried flowers from a succulent plant). The smaller black one is Native American from Arizona and has nothing in it:

We have a bunch of balls made from reeds in the vase we have out. It's on the table in this picture.