For me... the list is quite short...
I used an ancient Alcatel OT 300 for 8 years when I bought my n900 in 2010. I used this beast for 9 years. Well, almost. The one that I bought first fell down and so the usb port broke. It was 8 and a half years old but still usable My second n900 is in perfect condition (I bought it from another forum's member in my country - it is original and almost as new as a brand new device) so I used it until... Until my family life reached the point when popular apps are needed to communicate with each other, get things done, etc (at least I tried to set syncing Maemo calendar with Google's but without success)... So I bought my brother's iPhone 6 (in 2019 april or may). Then I cooked its CPU... Hahahaha... It was simply overheated in the car during navigation... It cannot be fixed. So I started to use my wife's Samsung Galaxy A5 (2015) and bought her another Samsung (XCover 4).
I'm using the A5 since then. There is a Sailfish port available for it but never tried that... Since I bought a Samsung smartwatch I need Samsung's OS on it. I used LineageOS for a while but then I found a custom rom that is built on Samsung's one (Xtreme OS - based on Android 7.1.1) so I'm using this at the moment.
My n900 is still in use for some hacking, listening to music in car (I really miss that fm transmitter...) but it is manly turned off and sits on a shelf...

I'm waiting for Leste now or maybe Sailfish. But I really need apps that at least could communicate the ones available for Android/iOS. I cannot tell my whole family to use other apps... And I would like to use my (or another) smartwatch. So that would be cool