I have an 8. It’s my third iPhone. I’ve had one for probably over 10 years and never turned one off. I’ve never had a problem either. The one thing that I do is check online as my phones age (like 4-5 years) and watch for user complaints regarding issues with OS updates on older phones. When they begin to show up, I wait for a further update or decide it’s replacement time. Just don’t turn it off and don’t get advice from Best Buy. You can Google everything you need to know about it.