Very happy with my Lumia 735 running Windows Phone 8.1, so I bought a Lumia 650 for my wife, but some things are bugging me about Windows 10 Mobile.
Anything that I 'back' out of seems to stay alive, even settings. Of course "apps don't cost anything when they lose focus", but when you're 'alt-tabbing' between two apps, it's painful if you have 10 others open.
Is this 'normal'? Is there an option to say "back means kill; if I'm not finished I'll hit Start"?