How often do you buy a new car? A new house? A new couch? A new raincoat, fridge, or washer and dryer?

And now: How often do you get a new cell phone?

Clearly, the upgrade cycle plays a much bigger role in the tech industry than in any other realm of consumer goods. Most people wouldn't be embarrassed to drive a 2009 Toyota Camry or to put their food in a 2002 refrigerator (or even a 1992 fridge). But walk around with a four-year-old iPhone, and people think you're some kind of caveman.

The tech companies are fully aware of this, of course. They exploit it. Software companies crank out new Microsoft Offices or Intuit Quickens more or less every year, counting on our fear of obsolescence to drive our dutiful upgrades. New Every Two is no longer officially Verizon Wireless's marketing platform, but Americans still buy new phones, on average, about every 22 months. AT&T and T-Mobile just introduced plans that encourage their customers to upgrade their phones at least every year.

It would be easy to sweep all tech companies into the same pile, to mock their cynicism and manipulation, to accuse them of planned obsolescence on a criminal scale.

Take Apple, for example. The iPad has been the best-selling tablet since its debut. We count on a revised, better, feature-enhanced iPad model every year—and that puts Apple under certain pressure. How do you improve your product every single year, especially when a large part of its appeal is simplicity?

Apple added the extraordinarily sharp, high-resolution Retina screen to the iPad 3, released in early 2012, just as it had to the 2010 iPhone 4. So what screen did the new iPad mini get in late 2012? The old screen, not the Retina. To many, it appeared that Apple withheld a valuable feature so that it would have an enticing upgrade ready for the next version.

On an industry scale, it's hard to spot obvious patterns of planned obsolescence. In the cell phone and tablet worlds, in particular, the competition is so intense that manufacturers can't afford to play Withhold the Feature. When a new technology is ready for prime time (and sometimes even sooner), they bake it in and start promoting it. It would be hard to imagine Samsung or Microsoft, each desperate to compete with Apple, saying, “That's an awfully attractive feature; let's save it for next year.”

And there's more reassuring news when you begin to consider different kinds of electronics. The PC cycle was once New Every Two, too. But these days Macs and PCs chug along for five, six or seven years before we replace them. That is largely because of the rise of the tablet and partly because there's not much innovation in PCs anymore.

Finally, remember this: we're not a bunch of trained sheep, conditioned to buy when the tech companies command us. You are perfectly capable of resisting the lure of a new model if the previous one is still fast enough for the software you want to use; utility, not the insecurity of being left behind, should drive your decisions.

Consider whether the new features offered in this year's model are genuinely worth the upgrade. Some will make a big, time-saving difference to your life: upshifting to a 4G LTE phone with far faster, more reliable Internet connections, for example. Others, like some of the gimmicky features on the Samsung Galaxy S phones, are little more than half-baked demo-ware. (Voice translator app, anyone?)

Yes, it's true that the engine of technology upgrades—especially in phones and tablets—runs faster and hotter than in other areas of consumer-dom. But the dynamic isn't as simple as: “We're the pawns, they're our calculating overlords.” The cycles are driven by even stronger factors: technological progress, the rise and fall of gadget categories, and our own lust for the new. In short, just because you're eligible for an upgrade doesn't mean you have to take it.

The annual obsolescence calendar: