As to annoyance, I owned Toyotas for decades. My "fondest" memories are of taking the car in for "service", which usually meant going 25 miles to the dealer and waiting four hours for them to get to my car, and then paying the ridiculous bill. This DOES NOT HAPPEN with my Teslas. 190,000 miles, no service, one repair, eight years. This is the NORM, not some crap-shoot luck.
The bad luck people will try to say that service centers need to be close and numerous, but they are simply wrong. I live in Central California, see dozens or hundreds of Teslas on the road every day, but when you go to the Service Center, which are few and very far between, it's crickets. Electrics last longer, make less noise, pollute about one-eighth of gas cars, need less service and repairs. And Tesla is King of the Pack.
Your sis could have bad service experiences way easier with a conventional car at conventional dealers. I've been there. For years and years and years. Tesla opened my eyes.