Iāve had monthly AppleCare+ on a 2018 12.9 inch iPad Pro and had a great experience with a support incident at the end of 2023, 5 years after the original purchase. I noticed just a slight decrease in battery performance. I was able to do a remote session and determined the battery was just below the 80% threshold. I booked and in store appointment where a Genius tested the device again and after confirming the same result I got new replacement unit (no charge because of the coverage). While Iāve been paying Ā£5.99 per month for over 5 years, I felt like itās worth mentioning the replacement of a device for battery drain over an extended period. Itās a nice additional potential perk of AppleCare.
I always get torn on Apple Care. In @Bazza_Robās example, heās paid Ā£360 and had a battery replacement, BUT he may have had all sorts of issues. In the end youāre buying insurance.
I would probably buy it on an Apple Laptop as Iād buy that for the long term and with it being a portable device, itās more likely to be damaged. For a Phone I prefer to buy a case and cross my fingers that nothing goes wrong in the 2/3 years that I have it. Anything smaller I wouldnāt buy it.
I do love the $50k option that if they need to, Apple will fly someone to you.
I never purchased AppleCare for our company iMacs, only for MacBooks and iPads.
We were a Windows shop, with only a handful of Macs, when we started switching other users to Mac in 2009. Of our first order of 60 iMacs all but 2 (or 3?) of the iMacs were still in service in mid 2017. Of those still running I had replaced the spinning hard drive in two, out of warranty, machines.
Insurance is a numbers game. I canāt recall the exact figures but I had calculated I would need to lose something like 8 iMacs during the warranty period to break even on AppleCare. We didnāt have a problem with any of them within the first five years.
OTOH I had one manager destroy two iPads in the first 18 months. Then a third around a year later, and that oneās replacement was dropped and broken by a co-worker.
I purchased AppleCare for my 2020 iPadPro but not for my M1 MacBook Air.
Similar personal experience: we still have a 2010 MBP and 2011 27" iMac running daily at our house. Both had AppleCare, neither has required work. Since Costco doubles the manufacturer warranty on all electronics, and Costco Visa adds another 2 years, I decided to forgo the AppleCare on my ā22 M1 MBP. Iāve had it less than 2 years, but so far it is following in its predecessorsā footsteps and running perfectly well, hardware-wise. Theyāve all had a handful of software issues, but those were all typically easy to resolve.
I bought AppleCare for the first time last autumn, because of this forum.
My last two iPads Iāve dropped and cracked the screen. When I bought the iPad Pro 12.9 inch I decided to get AppleCare in case I wanted to go for a trifecta.
I discovered a fault with my new iPad a month after purchase. I was covered by the warranty and UK/EU consumer laws anyway, but because I had AppleCare, Apple sent out a replacement device the next day so I didnāt have to go without an iPad. I was very impressed.
I wouldnāt buy it for my MBP I donāt think, the warranty would suffice and Appleās support is great.
I wonāt bother with my phone either since Iāve got it in an OtterBox case anyway.
Edited to add: I feel like my post didnāt have a conclusion. My conclusion is for me AppleCare is sensible for my iPads given that I keep breaking them!
AppleCare is not available where I live, nor has it ever been. If a device is bought in another country with AC, local authorised service centres sometimes frown upon that though I donāt think theyāve refused repairs as such. Iām not sure theyād honour device replacements though ā this would probably have to go through Apple.
Local authorised resellers try to sell their own 2- and 3-year extended warranties which only they will then honour but these do not cover replacements due to accidental damage and other benefits included with AC.
Looked at my Apple devices history list. I went through nine Macs, ten iPhones, six iPads and two Watches over the years without a single issue outside the 1-year warranty. Only one iPhone needed in-warranty repair due to a dead motherboard (the 6S Plus). I also never caused any major accidental damage. Iām not sure whether I was just lucky here but based on this Iām not sure Iād opt for AC anyway.
I bought an iPad Air from Costco and also purchased Apple Care plus. Fast forward a year, iPad stops powering on. Technician at the Genius Bar ran diagnostics, couldnāt figure out the issue and sent it off to remote service center. Few days later, iPad was mailed back to me to me stating
āThe reason your product isnāt working is because of unauthorized modifications that were made to it. Our warranty doesnāt cover issues caused by unauthorized modifications.ā
But, no mention of the exact unauthorized modifications that were made 
I called Apple Support and lady who answered the call genuinely tried to help me, but she couldnāt figure out exact reason.
I know you have to take my word here, but I did not make any changes whatsoever! Anyway I take it back to store, but Genius Bar technician said decision is final and canāt help me I thanked him for the looking into it and drove back home with a bricked iPad which wonāt power on! Thatās my super sad story with Apple Care Plus. Good to get it out, I guess 
Apple customer service is not what it used to be some years back. If they decided not to help you, you have no respite.
Did you try returning it to Costco? They double Appleās one year warranty. It seems that if it ājust stopped powering onā then that would be covered at Costco. It doesnāt hurt to try.