I chose a dining room rug that is big enough for my table when it is expanded, but an alternative would be to buy a smaller rug and store it away on the rare occasions when the table is at its full length.

If you think you will only expand the table a few times a year then get the smaller rug and store it temporarily as Fun2B suggests.

I tend to keep most of my dining room table leaves in all the time because I am not crazy about the way the table looks when it's smaller on the large rug...

I would go without one unless you really don't think you would use the larger table more than once or twice a yr- then I would probably get a smaller one...

I dislike rugs under dining tables and so would forgo!