Gas water heaters are less expensive to run than electric models and have a faster hot water recovery rate, which is attractive to large families. In the United States, gas powered water heaters are used in 60 percent of residences, making them the heater of choice as of 2015.
Some lifetime warranties cover the product for as long as you own it, which means the warranty is disclaimed (or voided) the moment it is resold or given away. Look for the word limited in front of the words lifetime warranty, which will be accompanied by language (usually in fine print) explaining its terms.
The expiration date of a drug is estimated using stability testing under good manufacturing practices as determined by the Food and Drug Administration (FDA). Drug products marketed in the US typically have an expiration that extends from 12 to 60 months from the time of manufacturer. At the pharmacy, beyond-use dates are often put on the prescription bottle label given to the patient.