Warranty for 6 months, right to complain for 18 months after that.

The difference is the burden of proof. For the initial 6 months, the manufacturer/store has to prove the item was not somehow defective from the beginning, due to manufacturing errors or similar mishaps, even if it broke 5 months and 29 days after the sale.

In the following 18 months, the burden of proof shifts to the buyer, to prove that the fault did not happen to due mistreatment during (ab)use of the item.

That's how it is in Denmark, at least.

In theory maybe. In practice handing it in to a seller with for example a faulty PSU or dead backlight your implicit claim as the buyer is that it was not manufactured to spec (to last at least those two years) and they would have a hard time fighting that claim unless there are obvious traces of mechanical abuse.

I don't know the detail, but the way you put it, "prove that the fault did not happen to due mistreatment" basically means that user has to prove the he didn't do something. I can prove that I did something, but prove I didn't do, that's a whole lot different.

That's why some manufacturers put water "sensors" in cellphones; once water enters, the "sensor" (in quotes because it's not an electronic part) changes its state forever revealing that water poured into the phone even well after it has been cleaned and dried.

Doesn't that make sense, though? If you have a physical product that you use daily, I don't think it's entirely unreasonable to ask how a failure after 700+ uses (or many, many more) can be confirmed as a manufacturing issue and not use [over|mis|ab]use.

I don't think overuses should be a reasonable cause for defects within 2 years. If 99.9% of users use it less than X, then covering the last 0.1% is not a significant issue.

The top 5% on the other hand are IMO within normal usage patterns.

The exceptions seem to focus on using consumer products like a coffee maker in an industrial setting. But, 2 years is rather short term to be replacing these devices not to mention the overhead of a regular breakdown > replacement process.

Yes, I think it does. I find it a reasonable balance between weeding out early failures and not letting customers get away with abusing their devices and still claiming a warranty repair.

How can a user prove they didn't misuse an item, though?

That would depend on the specific item, I'm sure. For example you can tell if a phone has ever been wet because there will be signs on the interior. No situation will be perfect but at some point the burden of proof has to shift from the company to the user. I think six months is probably a bit soon but sometime between that and two years seems reasonable to me.

Six months, not two years. I personally tend to ignore warranty periods of under a year anyways, since products with such short warranty periods (30-90 days is common here in the US) tend to be cheaper to replace than to get warranty service on anyways.

On the other hand, warranty here in the US can be annoying to deal with anyways--I've failed twice at getting replacements for Samsung flash memory cards that have been in production for less than their warranty period. There a some problems (microsd becoming read-only) that can't be caused by user misuse. That might be more reflective of Samsung as a company, however I've had similar issues with other companies as well.

In isolation, maybe, but those 2 additional years are hardly free.