I found this article interesting because it is true.  Laptops by design are not as stable of a machine as a desktop.  Consider the processors are normally half the power of desktops, they are mobile devices that constantly get moved and jostled around, and normally have cheaper parts (like the paper thin keyboard). Laptop parts are also twice as expensive to replace as desktop parts on average as well.  Check out the full article from Tom's Hardware:

That's right, you NEED a new laptop.

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We all love shiny new computers, which is never more true than when it comes to laptops. Unlike with desktop machines, a laptop is a complete package that typically evolves as a whole.

With a laptop, you're not going to upgrade the display or keyboard, and you can forget about upgrading the internals. All those reasons aside, there's now research that suggests that keeping a laptop beyond three years is usually more trouble than its worth.

Companies still working with tightened belts may be pressured to stave off the replacement cycle, but that could end up costing more, according to tech analyst Jack Gold.

Computerworld reports that Gold has come up with a cost model that estimates the cost of maintaining a laptop for two years beyond the initial three is $960 – which may end up costing more than just purchasing a new one at the end of year three.

As the laptop ages, it is more prone to failures of worn items such as the hard drive, keyboard and battery. The relatively slower old machine may also not be as productive as a newer model, also costing the company some money.

So there you have it – yet another reason to have shiny new things more often!