You do not have to do this to get warranty service by law. They just want your contact info so they can spam you.

No, warranty is covered by European law.

I have used warranties many times, but rarely bothered to register at time of purchase. In my experience, if you go to use a warranty, they’ll just ask for proof of purchase (if they ask for anything at all). I think the point of warranty registration is in case you need to use the warranty later, but you lose your receipt.

I’ve registered my Bose speakers. It actually made it easier to talk to customer service when I was having trouble pairing up a soundbar.

Personal stuff: No. Warranty is still valid. Plus the place I bought it are legally required to handle warranty related issues as well.

Corporate stuff: Sometimes. It’s not required, but it makes it a lot easier when I can choose the device in question from a drop-down menu of serial numbers to get the exact info/stuff I need. A lot of vendors track issues by serial number, and it’s an easy way for me to keep track as well.

https://www.consumerreports.org/cro/news/2014/07/do-you-really-have-to-fill-out-those-product-registration-cards/index.htm

ETA: link!
https://consumer.ftc.gov/articles/warranties

This ensures you, the original owner, can get service without the need of a receipt later down the road. It’s similar to voting registration in the US; you’ve proven at the time of registration that you’ve made the purchase so this card negates the need to prove it again.

Although, having worked in consumer electronics for 25+ years, if you’re buying something from a trusted local dealer, be sure to ask them if you should register. They may be able to fudge the purchase date and warranty period for you if you need service.

Moreover, much of today’s consumer electronics are so cheap and outdated within a year that most people just throw crap away and buy a replacement rather than get it fixed. I have seen some inexpensive products actually cost more to get fixed under warranty (if you have to ship at your expense) than to buy the replacement product.

Ironically, it’s probably the case that I register the stuff I expect to last longer than the warranty. It’s an easy way to provide the serial number and my info to the manufacturer and confirm if it’s under warranty or not. It also registers you for things such as firmware updates or recalls. So, a $1500 camera, yes. A $30 battery pack, no. A $200 speaker bar, yes. I also save all my boxes because they’re the perfect vessel for shipping if they need repair.

General rule of thumb is to only get a warranty for things that you cant easily replace. i.e a 10 dollar keyboard from walmart doesnt need a warranty. A 3,000 dollar gaming computer probably does. Companies charge more money for warranties than it costs them to honor them. That is how they make money and it is why they are pushed as hard as they are.

I registered a bunch of baby products like the crib and stroller because I wanted to be notified if there was a recall.

Depends how expensive it is to replace. Up to a couple hundred, no. Over that yes

Only for computers, phones, tablets.

Usually no. But all my festool tools get registered since they are all $$$$$$

Yeah, if a company forces me to do so (Razer, JBL). Most companies don’t require registration for warranty, at least in my country. All you need is the original invoice. When you want to claim a warranty, you need to fill out a form on that company’s website which asks for your details like name, phone number, email, and physical address, alongside the original invoice. That’s it, no prior registration required.