ShelfYears

The full cross-cut

What actually expires in a garage

Every product on this site in one list, ordered by how fast it goes off in a sealed container. The top is what to check before you use it this season. The bottom is what you can stop thinking about.

Updated

The garage is the worst room in the house for chemistry

Not because it is dirty. Because it swings. A room inside the house sits within a few degrees of the same temperature all year. An attached garage tracks the weather a few hours behind, and an uninsulated shed does worse than the weather — it bakes under an afternoon sun and drops below freezing on a clear night. The same shelf can move 40 degrees between breakfast and mid-afternoon in April.

Chemistry cares about that more than it cares about the calendar. Warmth speeds up every reaction that ages a product, and the cold breaks apart anything that is stirred together rather than dissolved. Two clocks, both running, both faster in the garage than anywhere else you could have put the bottle. Why heat and freeze–thaw are the real clock is the long version.

The fast lane is fuel; the slow shelf is additives and aerosols

Fuel sits at the top of this list and it always will. Pump gasoline is measured in months, a self-mixed two-stroke batch in weeks. Fuel is a blend of light, reactive hydrocarbons that starts changing the day it leaves the refinery, and warmth, air and — in ethanol blends — humidity all push it along. If one thing in your garage is older than you think, it is the can by the mower.

The bottom of the list is quieter: sealed additive packages, aerosols with an intact valve, heavy oils and greases, solvent-based products with nothing volatile left to lose. For a lot of them the honest answer is that there is no meaningful sealed clock at all, so they get their own group at the end of the table instead of a made-up number. A window nobody has measured is not a window.

Fastest to go off, first

Sealed window first; the opened window and the consequence beside it
Product Rack Sealed Opened If you use it anyway
2-cycle mix Fuels 30–60 days (self-mixed) 30–60 days Equipment damage
Gasoline Fuels 3–6 months 1–3 months Equipment damage
Diesel Fuels 6–12 months 1–6 months Equipment damage
Ethanol-free gas Fuels 6 months – 5+ years 3 months – 2 years Equipment damage
Bleach Cleaning chemicals About 1 year About 1 year Degraded performance
Brake cleaner Shop consumables 1–2 years Same 1–2 years Degraded performance
Brake fluid Automotive fluids 1–2 years About 6 months Safety issue
Caulk Paints & adhesives 12 months Weeks Degraded performance
Chlorine tablets Yard, pool & pest 1–5 years One pool season Safety issue
Construction adhesive Paints & adhesives 12–18 months Weeks at best Equipment damage
DEF (diesel exhaust fluid) Automotive fluids 1–3 years, by temperature Same temperature clock Degraded performance
Disinfectant wipes Cleaning chemicals 12–24 months The same 12–24 months Degraded performance
Duct tape Shop consumables About 1 year 1 year from manufacture Degraded performance
Hydrogen peroxide Cleaning chemicals 1–3 years 1–6 months Degraded performance
Kerosene Fuels 1–2 years One heating season Equipment damage
Laundry detergent Cleaning chemicals 12–18 months 6 months Degraded performance
Pool shock Yard, pool & pest 1–5 years One pool season Safety issue
Sandpaper (adhesive-backed) Shop consumables About 1 year 6–8 months in the shop Degraded performance
Silicone sealant Paints & adhesives 12–18 months Weeks Equipment damage
Spray foam Paints & adhesives 12–18 months 30 days on a gun Degraded performance
Super glue Paints & adhesives 12–24 months Weeks, once air gets in Degraded performance
Laundry pods Cleaning chemicals About 15 months About 6 months Degraded performance
Disinfectant spray Cleaning chemicals 18–24 months The same 18–24 months Degraded performance
Carb cleaner Shop consumables 2–3 years Same 2–3 years Degraded performance
Dish soap Cleaning chemicals About 2 years About 2 years Harmless
Epoxy Paints & adhesives 2–3 years 2 years, if the parts stay apart Equipment damage
Grass seed Yard, pool & pest 2–3 years Within 1 year Degraded performance
Lacquer Paints & adhesives 2 years 6 months if catalyzed Degraded performance
Latex paint Paints & adhesives 2–3 years About 2 years Equipment damage
Mouse bait Yard, pool & pest 2–3 years Condition, not calendar Degraded performance
Oil-based paint Paints & adhesives 2–5 years Until it skins over Degraded performance
Pesticide concentrate Yard, pool & pest 2–3 years or more 1–2 seasons Degraded performance
Polyurethane Paints & adhesives 2–3 years Until it skins over Degraded performance
Pool test strips Yard, pool & pest 2–3 years Until the printed date Degraded performance
Rubbing alcohol Cleaning chemicals 2–3 years The same 2–3 years Degraded performance
Silicone spray Shop consumables About 2 years Same 2 years Degraded performance
Spray paint Paints & adhesives 2–5 years Until the valve quits Degraded performance
Starting fluid Automotive fluids 2 years Same 2 years from the date code Degraded performance
Threadlocker Paints & adhesives 24 months Same 2-year clock Equipment damage
Wasp spray Yard, pool & pest 2–3 years or more As long as the can holds Degraded performance
Wood glue Paints & adhesives 2+ years Until it thickens Degraded performance
Liquid fertilizer Yard, pool & pest 3–4 years or more 3–4 years, cap on Degraded performance
Paint thinner Shop consumables 3+ years 6 months Degraded performance
Wood stain Paints & adhesives 3 years Until it skins over Degraded performance
Bar and chain oil Automotive fluids 4 years Up to 4 years Degraded performance
Weed killer (glyphosate) Yard, pool & pest 4–8 years 2–8 years Degraded performance
Algaecide Yard, pool & pest Up to 5 years 5 years, if it never freezes Degraded performance
Batteries (alkaline, lithium, rechargeable) Shop consumables 5–10 years (alkaline) The device sets the clock Equipment damage
Fuel stabilizer Fuels About 5 years 2 years Degraded performance
Gear oil Automotive fluids 5 years 2–3 years Degraded performance
Grease Shop consumables About 5 years Not rated once opened Degraded performance
Motor oil Automotive fluids About 5 years 2–3 years Harmless
Power steering fluid Automotive fluids 5 years 2–3 years Degraded performance
Primer (paint) Paints & adhesives 5 years 1–2 years Degraded performance
Synthetic oil Automotive fluids 5 years 2–3 years Harmless
Transmission fluid Automotive fluids 5 years 2–3 years Degraded performance
WD-40 & penetrating oil Shop consumables 5+ years Same 5+ years Harmless
Antifreeze Automotive fluids 8–10 years Doesn't meaningfully expire capped Degraded performance
The stuff that outlives you — no meaningful sealed clock, so no invented number
Ammonia Cleaning chemicals Doesn't meaningfully expire sealed Weakens as it airs out Degraded performance
Cleaning vinegar Cleaning chemicals Doesn't meaningfully expire Doesn't meaningfully expire Harmless
Drain cleaner Cleaning chemicals Doesn't meaningfully expire sealed Doesn't meaningfully expire Degraded performance
Granular fertilizer Yard, pool & pest Doesn't meaningfully expire Indefinite, kept dry Harmless
Ice melt Yard, pool & pest Doesn't meaningfully expire Indefinite, kept dry Harmless
Insect repellent Yard, pool & pest Doesn't meaningfully expire Condition, not calendar Degraded performance
Lamp oil Fuels Indefinite, sealed Years — cap it tight Degraded performance
Muriatic acid Yard, pool & pest Doesn't meaningfully expire Limited by the bottle Safety issue
Octane booster Fuels No expiration date No expiration — inspect first Harmless
Oven cleaner Cleaning chemicals Doesn't meaningfully expire sealed Doesn't meaningfully expire Degraded performance
Windshield washer fluid Automotive fluids Doesn't meaningfully expire sealed As long as it stays clean and capped Degraded performance

Fast is not the same as dangerous

The last column is the one worth reading twice. How fast a product goes off and what happens when you use it anyway are separate questions, and they do not line up. Plenty of things near the top of this list fail harmlessly — you notice, you buy another one, nothing else happens. Plenty of things with long windows carry a heavier verdict when they finally do fail, because the failure is invisible until the moment it matters.

That column is the site's actual answer, and it is the part a search result will not commit to. How the verdicts work, and what a shelf life on a label is really promising.