All my ammo is kept in a temperature/humidity controlled environment. I have 10+ year old ammo I would have no problem trusting my life on.
The 15 rounds I carry for self defense (In my snub nose revolver and 2 speed strips) and 17 rounds for my 9mm Shield (Two-8 round mags and 1 in the chamber) depending on which gun I carry, gets shot up at the range every 6 months or so to keep my skill level up along with a box of 50 target ammo and more carry ammo.
This keeps ammo in my carry gun fresh. JMO.

Stay SAFE and shoot often!