01

Have you ever come home tired and hungry and decided dinner is either an omelette or a bag of chips? I have, more often than my taste buds would like. The omelette wins. But there are only two eggs left in the carton at the back of the fridge, and the best-before date printed on it passed two weeks ago.

So I do what Google tells me and float an egg in a bowl of water. A fresh egg supposedly sinks, while one that stands on end or floats is older, though not necessarily bad. I'm too hungry for the physics, and even Google admits the test can't say for certain. An egg keeps its secrets. You can't sniff it or see inside it, and the only way to find out is the one thing you can't undo. You have to crack it.

What I learnt later is that these dates are really cautious suggestions. According to the US Department of Agriculture, a "use by" or "best before" date on eggs is a guide to quality. It marks when their quality starts to dip, not a death sentence for dinner.

Plenty of the dates we live by work the same way. Some come from parents, some from early managers. Stay at least two years in a job. Put your head down and do the work, and people will notice. Never give up a sure thing. Each was offered with care and was true once. I've come to think of them as best-before beliefs.

One friend ignored that last rule. His job was one most people would have envied, but it was taking more than he had left to give, so he asked for six months off. When his employer said no, he resigned, trusting a warm promise that he could come back any time. He couldn't. The team moved on, a restructuring cut jobs anyway, and the job market cooled. Most of us around him didn't understand why he walked away, especially with no new job lined up. He could afford the gamble, which not everyone can, but I still didn't see why he'd take it. I only understood a year later, when he told me he wouldn't trade those months for anything.

Sooner or later, we have to make a choice about the role that was right three years ago, the offer in another country or the business idea tested in every way except launching it. And still we look outside for a best-before date to decide for us, rather than finding out for ourselves.

Part of what holds us back has a name – loss aversion. Daniel Kahneman, who won a Nobel Prize for his work with Amos Tversky, found that most people won't take a coin-toss bet that risks losing $100 unless they stand to win about $200. Losses simply weigh more. No wonder even two eggs of uncertain age feel worth guarding. Yet when the University of Chicago economist Steven Levitt invited people stuck on big decisions to let a coin toss decide, those told to make a change were happier six months later than those told to stay put.

Waiting feels safer than it is. None of this means flipping a coin for every decision, but holding still has a cost too.

Cracking an egg doesn't guarantee a good outcome. It guarantees an answer. If the yolk still looks yellow and bright, dinner is served. If not, at least you know the next step.

It's a chip party tonight.