Ballistol often,and keep them out of the wet. If wet..dry and apply Ballistol.
Maintain the environment with temp control and dehumidifier. I read where 70 degrees and 50% humidity was ideal for storage. Above all, keep clean and wiped down whenever handled. I use a silicone cloth and no rust for 30+ years in humid Mississippi valley in the Midwest.
I have said it many times here before,and worth repeating.I have stored my entire gun collection for almost six years by using only Remington oil.Looked and operated as good as the day they went into storage.Any lubricant marketed today can protect a gun for a month or two.But what can really out perform Remington oil with Teflon.( maybe grease ) Also important is the fact that this product dries leaving behind a Teflon coating,so it will never gum up actions.Meaning action disassembly to remove old lubricant gunk is never necessary.
I pack my safe with desiccants and try to keep the guns clean and oiled. But an engineer told me recently that desiccants attract moisture. In each pistol box I put rust inhibitor paper from Brownells.