I bought a white DS Lite when they first came out here in Australia. I think that was May or June. Anyhow, in November I noticed a few cracks that had suddenly appeared on the hinges.
So I sent it back to Nintendo to get fixed and they returned it to me free of charge, and free of ugly cracks. Unfortunately, the procedure for replacing the plastic on the hinge requires them to dismantle the top half of the unit. So those four square plugs near the top screen now have tiny dents in them, where the technician removed them to get to the screws.
Now, I personally prefer it this way, but if you think looking at bent plugs will distract you from playing way more than cracks in the hinge (that you can't see at all while playing) then I'd advise against sending it in.
I don't mean to comment negatively about Nintendo, their products, or their technicians. I was impressed at the turn around (a little over a week) and the fact that they fixed it for free, but there is a compromise that may be important to some people.