When to send thank you cards

When to send thank you cards

I just got a notice that a gift was purchased from our registry but it's on backorder. It will be sometime before I get the actual gift. When do I send the thank you card? Should I send it even without receiving the gift or should I wait until the gift comes in?

I waited until the gift came in..... *NM*

I would send it now - It's not the gift givers fault! *NM*