You can often go for many weeks where you do plug your phone in for charging but there is no need to shut it down. You normally do not have to shutdown your iPhone regularly.
Practice: Locate the Side or Sleep/Wake button on your phone and put your iPhone to sleep and wake the phone with either the Sleep/Wake button or the Home button.
But remember, putting your phone to sleep will not stop your phone from ringing during your church service. Putting your phone to sleep is an action that you will do frequently. It is a simple action that will wake your phone and allow you to unlock your phone to make calls or perform other actions. Wake your phone by pressing the Sleep/Wake button or by pressing the Home button. You can still receive phone calls and text messages. When you put your phone to sleep, the phone is still on and operating. It allows you to put your phone in your pocket without making butt calls, that is the accidental placement of a call when a person’s mobile phone is in a pocket or handbag. It will not take action if you touch the screen.
When you simply press the Sleep/Wake button on your phone, you are putting your phone to sleep and locking it. Find the Side or Sleep/Wake button on the upper right on your phone What does Sleep do?