Q: Is it ok to turn off your iphone in Every full charge to save battery life for important matter

I guess, that starting up the phone again will use more battery than if you put it into sleep mode by pressing the sleep button, Wi-fi and Bluetooth being switched off.

In case you are planing to store it for a longer time, check this:

If you want to store your device long term, two key factors will affect the overall health of your battery: the environmental temperature and the percentage of charge on the battery when it’s powered down for storage. Therefore, we recommend the following:

• Do not fully charge or fully discharge your device’s battery — charge it to around 50%. If you store a device when its battery is fully discharged, the battery could fall into a deep discharge state, which renders it incapable of holding a charge. Conversely, if you store it fully charged for an extended period of time, the battery may lose some capacity, leading to shorter battery life.
• Power down the device to avoid additional battery use.
• Place your device in a cool, moisture-free environment that’s less than 90° F (32° C).
• If you plan to store your device for longer than six months, charge it to 50% every six months.

Depending on how long you store your device, it may be in a low-battery state when you remove it from long-term storage. After it’s removed from storage, it may require 20 minutes of charging with the original adapter before you can use it.

copied from: https://www.apple.com/batteries/maximizing-performance/

Hi

Yes - it is OK to turn your iPhone off in order to preserve battery charge.

However, there are some other steps that you may find helpful in making the battery last longer, whilst still keeping your iPhone turned on.

Options include, for example, turning on Low Power Mode (via Settings > Battery), which reduces power consumption by keeping certain key functions available, whilst turning some others off.

More information and other tips:

https://www.apple.com/batteries/maximizing-performance/#iosdevicestips

Keep in mind also that the battery can be charged whenever you like.

The battery will not suffer any harm from regular charging, regardless of the charge level when charging begins.

There is no need to let the battery discharge fully before recharging it, nor any benefit to be gained from doing so.

More information:

https://www.apple.com/batteries/why-lithium-ion/

The phone is a communications device. If you turn it off, you will receive no communications. I have owned 3 iPhones and have never turned any of them off, and I have never had any battery problems with them. If you're worried about battery life, there are many, many spare charging options out there. Carry an extra cable, buy a Mophie, carry a battery pack, but don't turn your phone off or you're defeating the purpose of having a personal communications device.