Years. Often a decade or more. Realistically, longer than you’ll want to keep them.
Food-grade 304 stainless has no wear-out mechanism under normal kitchen use. It doesn’t have a coating to peel, a plastic that fatigues, or a surface that clouds. It’s the same material commercial kitchens have leaned on for decades precisely because it doesn’t give out.
What actually ages a steel container: almost nothing. It can pick up cosmetic scratches or minor dents, but those don’t affect whether it’s safe or usable. A brushed finish hides them well.
The one part that has a shorter life: the silicone lid seal. Seals are consumable — over years they can loosen or pick up odors. The fix is simple: rinse it separately now and then, dry it fully, and replace just the seal if it ever stops sealing. The container itself keeps going.
How to get the full lifespan: don’t leave it sitting wet for long stretches (304 resists rust but isn’t fully rust-proof if abused), skip harsh abrasives that scratch, and hand-dry the seal. That’s the entire maintenance list.
This is the quiet appeal of steel. You buy it, and then it just keeps being a container — through years of lunches, more than one phase of life, sometimes more than one kid. The material outlasts the reasons you bought it.
Food should be stored without doubt.