My rifles have been in there 1 year + no shooting, I just wipe them down every 6 months. One patch or two, of rem oil down the barrel to keep it safe from rust. A long with dehumidifier in the safe, charge every 3 weeks or so. I have a few pistols in there also, been fine. I bought some packs of Desiccants 1gm packets. I throw them around in the safe and in my ammo cans. Was like $10 on ebay for 100, well worth it.
I used to have a 380 sitting on my desk, I rarely wiped that down. Sat on my desk for about 5 months and never had a problem.
SHTF vs TEOTWAWKI you ask? SHTF, just some crap on the ceiling and walls, TEOTWAWKI end of the world as we know it. Orignally made by 9mm/®™©