The life of an Energizer battery, just like any battery, depends on the device in which it is being used. According to a science experiment done by Energy Quest, Energizer batteries last longer than both Eveready and Duracell.
The experiment that was set up by Energy Quest involved Eveready, Duracell, Energizer and Rayovac. These battery brands were placed in flashlights and left on until they died. The battery brand that lasted the longest was Rayovac, followed by Energizer, Duracell and Eveready. Energy Quest expected the Eveready batteries to go out first because they were the only non-alkaline batteries used in the experiment. However, Energy Quest predicted that the Duracell batteries were going to last the longest at the start of the experiment.