I use the native Reminders app on my iphone SE (iOS 11.4.1). I have the following question, which, I hope, is not too naive: after I have set the reminder up, should I leave the app running in the background after I close the phone down? With most apps, once I have finished using them and am shutting the phone down, I double-press the home button while seeing the home screen and then swipe up on the apps to close them. I have been doing that with Reminders, and it has not affected the punctual sounding of alerts when the reminder has been set to remind me at a day and time. But when set to remind me at a place, there seems sometimes to be a delay of up to 2 or 3 minutes. Could this be because I had closed the app? Should I leave it running even though the phone has been shut down?