So many haters here.
Here's an article "Run-Flat Tires: Pros and Cons":
https://cars.usnews.com/cars-trucks/...-pros-and-cons. It seems to confirm the stories I read about people driving on runflats with torn sides, as well as much farther than the promised minimum. A true runflat won't fail you!
On maintaining the correct pressure. The guy who installed my new winter set of runflat tyres inflated the left side ones as I told him, but the right side ones to the maximum allowed (provided on the tyre side) or even more: I only found that out a year after when doing the seasonal change for the next winter myself (that's when I inflate them). The tyres withstood that!
Those motherfuckers can fuck up even when you are watching them working where you wouldn't even imagine they could!
A spare wheel has another inconvenience: "-Damn it!!! -I hope you have a spare wheel. -Yes, I do. But I don't have two!" (a movie quote).