I have an electric toothbrush. It runs off batteries. When the batteries are good, my teeth get very clean, when the batteries start to fade, the toothbrush does a lesser job. Because I use the toothbrush so regularly, I don't notice the fading of the batteries. One day, the sound seems more dull than it should be and I wonder whether the batteries have ebbed to the point where the brush is nothing more than a novelty item, and no use to my dental hygiene.
Today I fitted two new Duracell Batteries into my toothbrush. There's a reason why Duracell are considered the best makers of batteries. It's because they make good batteries. My toothbrush was turned into a powertool of the utmost cleaning power.
I'm still buzzing.