I used the heck out of it, surprised it lasted that long.
35 yrs I use it once a month maybe
We use ours daily, if not hourly. 23 years.
i had one for 17 years! but still cursed when it gave up the ghost.
I had one which lasted over 30 years.
Except for my cast iron skillets and toaster oven, the microwave is all I use for cooking.
Bookmark.
Our first Amana lasted 25 years. After that it was a series of Chines magnetrons until I gave up on it. It was a 30" built-in over a matching oven. Big mistake. I should have gone 36". But now we have a 30" over-the-range model. More easily replaced but I hate the programming and the push-to-close latch. The latter is noisy when the wife is asleep upstairs.
Microwaves speed on into eternity.

I have done several post-mortem investigations on dead microwave ovens, and they really started to crap out when manufacturers started using aluminum wiring instead of copper in the power supply to save money.
Had a microwave “die” and then figured out it was a blown internal fuse. After I had bought a replacement. Then I had two microwaves.
The one I have now is over 15 years old.
When I retired, there was an ancient microwave in one of the buildings that had been there over 30 years. It hadn’t even been very well cared for.
My Father had one that lasted only 3 months.
That’s what happens when you cook a bowl of oatmeal for 6 hours.
Melted it.
They last until the warranty runs out..............
I still have my first microwave, a Litton, from ~1977.
It worked for a long time.
I afraid to take it apart, but it still looks good.
Its replacement is still working.
Four years sounds short....
Uncle Mike has lasted 10 years and counting.
My last three lasted 7 years apiece. Usually used them less than 2 mins once a day, occasionally twice.
Modern appliances are trash, with poorly designed, cheap electronics - half of which are unnecessary for features no one cares about. That’s why they only last a few years, while stuff designed 50-80 years ago lasts decades.
I found mine in the garbage about 12 years ago and fixed it and it still works fine. The latches are getting a little bit hinky. My brother probably has a 1974 microwave that still works, it looks like the station wagon in Family Vacation, that Chevy Chase movie.
Replace with air fryer to decease the grease. The CR best is $50