When should we start to care then? Ok, so they've got nukes now. NBD. 5 years from now we should worry...? Come on, seriously?
What are they going to do with them? They use them against us and that is the end of North Korea, period. Again, it is all about survival with these guys, even the crazy North Koreans. What could we do anyways? Sanction them? Invade them? Strike their nuclear facilities? That is, if we know where they are.
There are no good options, so what do you suggest we do?