I have used N2 quite a few times and do not see any real difference in terms of how long the air tyre pressure is maintained.
N2 helps when tyres are used in harsh conditions such as on a track. It's not really the nitrogen itself, air is almost 80% nitrogen, but rather the moisture in compressed air that causes the air pressure to go up.
For our DD, perhaps when running long distance, it's hardly going to help that much. Also it's good to check your tyres often, you may discover some object that is embedded in it. Always check your tyre pressure on a regular basis.