I've spoken of the North Korean policy of coping with lack of money by focusing on nuclear weapons and secret police (kooks, spooks, and nukes). Strategypage writes:
Some wonder how North Korea can continue to pay for nuclear weapons research, build new ballistic missiles and ships while refurbishing bases used for the missiles tests, new ships and still maintaining its commando forces. In North Korea there is now an emphasis on developing and building weapons that can threaten, harass or intimidate but not win a war. North Korean commandos, who are less than ten percent of army manpower, are still well equipped and taken care of. The navy is getting money for new submarines, either small ones for sneak attacks along the coast or a few large ones carrying long-range ballistic missiles. For the small boats there is the new K-35 anti-ship missile. North Korean hovercraft are being maintained, as these would be used for coastal raids. The rest of the military gets very little and the impact of that is becoming quite obvious.
They note that the army is being used as a virtual slave labor force. Which would explain expanded conscription classes despite the problem of having a potentially angry and desperate army in service.
But perhaps I'm not giving the North Koreans enough credit. Could the North Korean army really just be a system of internment camps that keep potentially subversive young men from being back on the block where they can be exposed to increasing anti-regime sentiment and where they might take up arms by going rebel?