Inside of a fire station in Livermore, California, there's a weird-looking, pear-shaped

light bulb dangling from an electrical cord.

It doesn't look too impressive.

It gives off considerably less light than a single candle on a birthday cake.

But that's partly because this little bulb, known as the centennial light, has been burning almost continuously for 124 years.

It stayed alive through two world wars, the first moon landing, and the rise of cell phones in the internet.

In modern life, it's hard to imagine anything we own lasting more than a century,

let alone a light bulb. So the centennial light raises a question.

If we could build a hundred-year light bulb at the turn of the 20th century,

why do modern light bulbs only last a fraction of its lifespan?

You have a much more complicated product at the end of the day,

so there can be more failure points, which might reduce the lifespan.

There's always these trade-offs with light bulbs.

For the Freakonomics Radio Network, this is the economics of everyday things.

I'm Zachary Crackett.

Today, light bulbs.

It's easy to take the light bulbs in our homes for granted.

Most of us don't even think about them until they need to be replaced. But reliable light wasn't always easy to come by. For so much of human history, light was just

either a candle or a lamp with some kind of horn or glass cover and a flame that had to be lit.

That's Jane Brocks. She's the author of the 2010 book, Brilliant, The Evolution of Artificial

Light. The wealthy had beeswax candles, which, you know, burned brightly and evenly

and did not stink. The poor had their tallow, which stank and

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