I have used DME so often that I can no longer keep track of the number of times I've used it! And with only one exception, I've gotten our info packet, with luggage tags, 4-5 weeks before departure. The only time, and it was just the one time, that we didn't get our packet before our departue day was when I booked a week before we were going to leave. DME needs at least 10 days to get the stuff printed and out to your home. My packet was waiting for me when I got home from that trip.
However, I have a friend who hasn't gotten her stuff at all on several occasions. There seems to be an increase in frequency of not getting the info packets. If you have booked in plenty of time, and don't get the packet by the 3rd week before travel, call DME and see if there is an issue.