The Syncwire Lightning cable I bought back in 2016 finally broke on me.

When I checked the receipt from when I bought it, I saw it came with a "lifetime warranty," so even though about three years had passed, I decided to ask support whether the warranty was still good.
Note: The warranty has since been changed to a maximum of 36 months.
I Reached Out to Support
You can contact support either through Amazon's site or via the support email address. I quickly sent off a message asking, "Can I make use of the warranty?" and got a reply almost immediately, asking me to send the information needed to process the warranty service.

I attached a photo of the broken cable, filled in the required information, and sent it off. After waiting a bit, I got a reply saying, "Your product will arrive within 2-4 business days."
The New Cable Arrived!
Two days later, the package showed up.

It came in the usual Amazon envelope.

Looks like Amazon handles the shipping.

Here's the new Lightning cable. Same model as the one I bought three years ago.

It's still the mainstream USB-Type A version. By the way, a Type C version is also available now.
It's certified with Apple MFi and the build quality is solid, so if you're going to buy an Apple Lightning cable, you're better off grabbing one of these and putting it to heavy use.

Here's what's inside the package.

According to the instruction sheet, the warranty has now been changed to a maximum of 36 months. You only get one year if you don't register, so when you buy a new one, make sure not to forget to register it.

Here's the new cable itself. This series uses nylon braiding and is very durable — even after three years of use, it never broke.

Compared to the old, broken cable. Looking at them side by side, you can see how worn out the old one looks from being abused on the go every day.

And of course, data transfer with a PC works without any issues.
Update: 3-Year Warranty Means You Can Use It Worry-Free
The lifetime warranty I used this time has already been discontinued, but even now there's still up to a 3-year warranty, so you can use it without worry every day on trips and business travel. Support is solid, and you can pick it up cheaper than the genuine Apple cable, so it's a cable I can definitely recommend.