Buyer's remorse. It’s been around forever and is especially rife in the gadget world, where every year there is a smaller, faster or cuter version of every device you own. But where a product’s life used to be measured in years, now it can be just months. In the cellphone market, this is particularly dangerous: You sign up for a 24 month relationship with a single gadget, but even as you pen your name on the line you know you’ll be tempted to cheat in less than a year.

Now, right or wrong, buyers are fighting back and trying to force manufacturers to give them cheap upgrades. Sometimes they have a case, but most of the time they’re just whining. Here are five of the worst examples we've seen this year.

iPhone 3G and 3GS

Apple seems to attract a lot of upgrade envy, possibly because of a relatively small and easy-to-understand product lineup, or possibly because the company gets publicity like no other. Right now the problem is the iPhone 3GS. Current iPhone 3G owners wanting to get their hands on the new phone will have to pay $700 for the top-of-the-line 32-GB handset, $400 more than the cost for new customers.

This isn’t the first time Apple has annoyed its customers with iPhone pricing — the original iPhone cost $600 on launch and then dropped to $400 just a couple of months later. In that case, Apple actually listened to all the whiners and issued a $100 store credit to early adopters.

The difference this time, though, is that people who signed up for a two-year contract are now complaining, even though they knew this would happen. They bought a subsidized handset in return for being a customer for the next two years, and now they want to change their minds. Our advice? Suck it up, and quit whining.

Kindle 2 and DX

Amazon certainly engaged in some questionable product-launch scheduling this year. The Kindle 2 replaced the original Kindle, and barely a month after it started shipping, along came the Kindle DX, a bigger, more expensive version of the e-book reader with PDF-compatibility and a display viewable in landscape format.

There was an outcry, and many Kindle 2 buyers tried to return their perfectly good devices so they could upgrade to the new one. “Unfair!" they cried, saying that Amazon was somehow in the wrong for announcing two products so close to each other.

But this is, again, nonsense. The Kindle and the Kindle DX are quite different products. One is a reader for novels and the like, the other is for textbooks and research papers. The DX is really too big to carry for most people, but it is still a lot smaller than a suitcase full of reference books.

Analog TV and Digital TV

You might laugh, but it’s possible that somebody, somewhere, has bought an analog-only TV this year. If the message about the big switch-off was so badly communicated that the Obama administration delayed the throwing of that switch until today, it was badly communicated enough that some hillbilly might have sprung for a new set in the last few months.

In this case, though, there really is someone to blame. Sure, the cousin-marriers might be excused for not keeping on top of the tech news, but the TV stores cannot. We imagine, though, that it is very unlikely: Most of the suppliers, and even the cable companies, are lying about the digital switch to get people to upgrade to unneeded new plans and equipment.

Personal GPS and Every Cellphone

If you have recently bought a personal GPS device, then you really shouldn’t have bothered. Many cellphones have one already, and in the next year or so we think that GPS will become as ubiquitous in phones as cameras have.

While in-car GPS units still have advantages — they’re harder to steal if they come as standard, they can hook into the car’s speakers, and they can have a big, juicy antenna to suck in the satellite signals, personal GPS devices have little to recommend them over the ones in phones.

Megapixels and More Megapixels

Believe it or not, we've actually read complaints from D3 owners that they felt cheated by Nikon's announcement of the D3x, despite the fact that the cameras have almost completely opposite purposes. The older D3 is a dream camera for many. It has a 12-megapixel sensor which can see in the dark, and it costs around $5,000. If you have bought one of these, it's likely you know a lot about cameras and have plenty of experience.

The D3x, on the other hand, is a 24.5-megapixel monster that weighs in at $8,000 and is better suited to a brightly lit fashion studio than a dark sports stadium.

As we said, two completely different cameras in purpose, and yet even smart people, people willing to pay thousands for a camera, are seduced by megapixels. Is this buyer's remorse ... or just buyer's stupidity?