ricecake gave a good answer already. In the EU you have 2 years. In the first 12 months the company has to prove that it wasn't their fault, in the next 12 months you have to prove it was their fault.

If no such law is in place, nothing protects you from them using cheap materials that break after a few months.

E.g. I once had a free xbox-replica controller every year because their product was shit and it broke after ~6-9 months. They had to replace it and did so three times. Then I got my money back. Selling * doesn't work here.

Some countries have more consumer protections than the US does, and consumers from there are wary of the lack of assurances a lot of us products have.

To them, it's like being told you have to pay for your food at the restaurant even if they mess up your order and you don't get to eat it. It doesn't matter that the waiter probably isn't going to drop your food on the floor, throw it away and then give you a bill: the fact that they could makes you not want to go there.

Likewise, your watch will almost certainly not break via factory defect after more than a month, but the expectation is that if they sell you something it'll either last the expected lifetime or be suitably replaced or refunded on failure.

We're used to our particular blend of capitalist hellscape, so a company saying they'll replace things if they're obviously broken the moment you buy it, but beyond than you're out of luck just seems normal. It's on us to make sure they don't mail us subtly damaged microelectronics and tiny lithium bombs.