How long does it usually take to recieve my new equipment?

I recently moved.  I was originally told by Xfinity that I could just take my current equipment to my new place and a activate it there.  That all went smoothly.  A problem arose when I tried to use one of my streaming apps and I got a message saying I needed to upgrade my equipment and it asked me if I wanted to have it shipped to me.  I clicked on the the confirm button and it said it was on it's way.  My question is how long does it generally take to arrive and at what point should I be concerned if it hasn't arrived?