If you’re under warranty, and using the pump as you’re supposed to, you’re fine. Tandem tech support is pretty awesome. Broken screens are rare, but if it happens, they’ll refinance the pump.
I’m guessing that’s the “accidental damage” you’re most concerned about. Parents if kids on the Facebook groups often talk about experience with broken screens. Kids abuse the heck out of these things. I’ve seen very few adults manage to break a screen. I’m accident prone and drop mine all the time, and have never damaged the screen. They come with a tempered glass screen protector factory installed. That will break long before the screen.
They won’t cover the absurd, though. Like say you wore it scuba diving at 100 feet and it stops working, when it’s only rated to be submerged at a depth of 3 feet for 30 minutes. The reality is, it’s hard to prove something was damaged irresponsibly. You pretty much have to volunteer that information. What would happen in that case is the screen would display an error code and the message to call the tech support phone number immediately. The tech support person would tell you that code indicates water damage and ask about any water exposure you know of. If you tell them you wore it scuba diving, you would be denied a replacement. If you tell them if fell in the bathtub, that would indicate a manufacturing problem because the pump should be able to take that, and they would send a replacement. Not suggesting you be dishonest, just illustrating that they only know you broke the rules if you tell them so. Usually there’s very few questions asked, though. They just tell you the pump needs replaced and ship you a new or like-new refurbished one, and you return the old one.
The big thing they don’t cover is loss and/or theft. That’s why you should have the pump added to your home insurance or renter’s insurance policy. If you can’t exchange your pump for whatever reason, you’ll be charged for a new one.
I’ve had 2 replacements in nearly 5 years, but in both cases my pump was still functional and I was able to use it until the replacement arrived. One was because I called the an unrelated issue, and the person noted that my battery was out of spec. They’re not supposed to lose more then half their charge in 3 days, even though it was my own fault. I was ignoring alerts and the repeated vibrations drained the battery. I was happy to get a new pump, though, because I like things new and shiny. Another replacement I think was totally my fault. I suck out the remaining 15-20 units of insulin in a dead cartridge, and add it to the next. I was doing this whine it was still installed, and I think I damaged the pressure sensor. I started noticing I wasn’t getting the right amount of insulin, and there was like 60-80 units left in an empty cartridge. This wasn’t anywhere in their playbook, so I had to use a backdoor loophole where I had to talk to one of their CDEs and explain the problem, and she was able to replace the pump for me without any further questions. Now I make sure the cartridge is removed before screwing with the contents, and haven’t seen this problem again.