We never do actually. I think I would if I had a large party, but every time we've gone we've never waited more then 10-15 minutes for a table.
This last time we did a late lunch, and got seated within 5 minutes. Which was really nice.
We went with a lot of family several years ago and that was a time they should have had reservations. I think we waited a good hour for that one (but it was like a table for 17 people!)