Buy QUALITY ammo with sealed primers, ever notice how some primers are red or greenish blue around their edges on better ammo? That's because they're sealed at the edges with paint sealant at the factory and store MUCH longer (controls moisture issues). Store in new or better quality Military cans or equal, with intact undamaged rubber lid seals. Get high quality re-usable desiccant packs. Fill cans removing your ammo from the cardboard boxes (paper pulls moisture), you can leave the ammo in their plastic cases if you choose for stacking, if you do, write on the plastic case the date of purchase or manufacture and always store the newest ammo on the lowest levels. If you don't use the cases use baggies and write the appropriate info on the bag. Remember, oldest always on top! When your can is full (1" from the top) put a strip of Duct tape on it write in Sharpie (Perm Marker) the dates of the ammo in the can. Off the top of my head a full can is approx. 2,000 rds. The top 1" of the can I fill with 3 lg desiccant bags. Once a year I open the cans to inspect the ammo and re dry the desiccant in the oven. I do try to rotate stock, new stuff in new can with the oldest stuff shot first. Going to the range, buy 200rds shoot 100 (pulled from oldest inventory with the new 200 put in a new can). Ammo stored and maintained well can last decades. BTW, Cool, Dark, Dry spot is best.