A sarcastic yet true answer, but for me it was maybe 1 hour. I had a S6 Edge Plus. I went and thought I'd give Apple another try and get an iPhone 7 Plus. I hadn't owned an iPhone since the iPhone 4 and figured I'd see if it had gotten any better. In the store I thought I could get used to iOS again so I bought the 7 Plus. I got it home and literally in about one hour, I was ready to throw that thing into the wall. Apparently I've just been spoiled by Android. I drove back to the store and made it there maybe 10 minutes before they closed. I returned the iPhone and bought my S8+. Never looked back. But before THAT, shortest I ever went was maybe a year.