Sources & Methodology

ExpireGuide is built on verifiable data. Every replacement timeline, safety recommendation, and product lifespan figure on this site comes from one of the sources listed below. We cite specific sources on every individual item page.

Government Agencies

Consumer Product Safety Commission (CPSC)

The CPSC is the U.S. federal agency responsible for protecting the public from unreasonable risks of injury or death associated with consumer products. We reference CPSC guidelines for smoke detectors, carbon monoxide detectors, car seats, fire extinguishers, electrical safety, and product recall information. Website: cpsc.gov

National Fire Protection Association (NFPA)

The NFPA develops and publishes codes and standards intended to minimize the possibility and effects of fire. We reference NFPA standards for smoke detector replacement (10-year recommendation), fire extinguisher maintenance schedules, carbon monoxide detector guidelines, and electrical safety codes. Website: nfpa.org

Food and Drug Administration (FDA)

The FDA regulates food, drugs, cosmetics, and medical devices. We reference FDA guidelines for sunscreen expiration, medication shelf life, cosmetic expiration, and over-the-counter drug storage and expiration. Website: fda.gov

Environmental Protection Agency (EPA)

The EPA protects human health and the environment. We reference EPA guidelines for water filter replacement, radon test kits, air quality equipment, and water treatment systems. Website: epa.gov

National Highway Traffic Safety Administration (NHTSA)

The NHTSA is responsible for motor vehicle safety. We reference NHTSA guidelines for car seat expiration, tire safety, and vehicle safety equipment. Website: nhtsa.gov

Department of Energy (DOE)

We reference DOE guidelines for water heater efficiency and lifespan, HVAC system recommendations, weatherization, and energy-related home systems. Website: energy.gov

Industry Organizations

InterNACHI (International Association of Certified Home Inspectors)

InterNACHI publishes comprehensive life expectancy data for home systems, appliances, and building components based on field data from certified home inspectors. We reference their data for water heaters, HVAC systems, roofing, plumbing, electrical panels, and other home systems. Website: nachi.org

American Dental Association (ADA)

We reference ADA recommendations for toothbrush replacement frequency. Website: ada.org

American Academy of Ophthalmology (AAO)

We reference AAO guidelines for contact lens and contact lens case replacement. Website: aao.org

Snell Memorial Foundation

The Snell Foundation sets voluntary helmet safety standards that exceed government minimums. We reference their 5-year helmet replacement recommendation. Website: smf.org

How We Handle Conflicting Information

When sources disagree on a replacement timeline, we follow this hierarchy: government safety mandates take precedence over manufacturer recommendations, which take precedence over industry conventions, which take precedence over expert opinions. When we present a range (e.g., "5 to 10 years"), we explain what factors place an item at the shorter or longer end of that range.

We clearly label whether a timeline is a safety requirement ("NFPA recommends replacement every 10 years") or a quality-of-life suggestion ("most sleep experts recommend replacing pillows every 1 to 2 years"). The distinction matters, and we make it on every page.

Corrections

If you find an error, an outdated recommendation, or a more authoritative source for any data point on this site, please contact us at hello@expireguide.com. We review and respond to all correction requests.

Last updated: March 27, 2026