Elliot Chen has replaced his phone, in effect, on almost exactly the same week for three years running, a pattern he began tracking in a spreadsheet after his Lygon Street East barista asked, not unkindly, whether he was "doing alright" after watching him stare at a 19 per cent battery warning for the third morning that week.

"I used to think it was just bad luck," Chen said. "Then I looked at the dates. Year one, the slowdown started in October. Year two, October. This year, right on schedule, October. I don't think it's luck. I think it's choreography."

Chen's suspicion, as it turns out, has a hundred-year-old precedent. In December 1924, major lightbulb manufacturers including Osram, Philips and General Electric's international arm formed a cartel in Geneva, known as Phoebus, that divided up the world's lighting markets and, according to a detailed account in IEEE Spectrum, set a hard limit on how long a household bulb was allowed to last: 1,000 hours, down from a standard that had commonly reached 1,500 to 2,000 hours and, in some cases, well over 2,500. Factories were fined if their bulbs lasted too long. The average lifespan of a reference bulb fell from around 1,800 hours in 1926 to 1,205 hours within a decade. The arrangement collapsed with the outbreak of the Second World War, but historians credit it with naming, and arguably inventing, the strategy now known as planned obsolescence.

"I'm not saying my phone company got on a boat to Geneva," Chen said. "I'm saying someone, somewhere, clearly still has the minutes from that meeting." Chen's own device, he's quick to clarify, has never been proven to slow down on purpose by anyone with more authority than his barista, and he is careful to describe his schedule as a correlation rather than an accusation, mostly because he has signed an extended warranty and would prefer not to annoy anyone.

What began as mild frustration has, over three years, curdled into something closer to professional respect. Chen now pre-emptively budgets for a new phone every October the way other people budget for registration renewals, and has started referring to the month, without apparent irony, as "upgrade season," a term he invented himself and now cannot stop using.

"If they are doing it on purpose," he said, "I just think the scheduling is very good. I'd hate to lose that level of consistency to an actual bug fix."