Originally Posted by SouthArk370Z

There's not that much difference between dry air and dry Nitrogen. Most N2 is very dry; shop air can be wet. If you don't have a source for dry air, N2 is the way to go. If you have dry air available, N2 is a waste of money. Differences in leak-down rates are inconsequential, IMNSHO, but I don't mind giving my tires a shot of air every 1-3 months - it's a good time to inspect the tires and wheels. YMMV