It's bullshit. Source: I'm employed by a hardware startup in Europe, specifically one selling similar types of DIY hardware. Most of our products are kits requ

It's bullshit. Source: I'm employed by a hardware startup in Europe, specifically one selling similar types of DIY hardware. Most of our products are kits requiring soldering, and by far the most common cause of failure is user assembly errors. We offer great support trying to assist the customer in fixing any errors, but it is still the customer's fault if they really screw it up - which rarely happens. All non-trivial parts are 100% tested in the factory, and we explicitly instruct the customer to verify they function before installation. Defects do still happen, but are not very common. We'll just send a replacement without any fuss, because we budgeted for that. I do not believe long-term warranty requests have ever happened at our company.