Should I back up my iPhone before sending it for a battery replacement?

You should always have a backup when getting your phone serviced and only get it serviced by Apple or Authorized Apple Service provider. Usually the phone is not wiped by Apple when replacing the battery, but it is always recommended that you have a backup in case it does get wiped. I have never had them tell me to erase the data before they would replace the battery.

konthorn272 wrote:

I changed the battery of my iphone11, but the service staff told me that I need to erase all the data

You should back up regularly, even when not sending your phone for service, unless there is nothing you save on your phone that you would miss if your phone is lost, stolen, thrown under a bus or dropped in a 🚽: How to back up your iPhone, iPad, and iPod touch - Apple Support.

These are the recommended steps to perform before your iPhone is serviced at an Apple Store or Authorized Service Provider:--> Get your iPhone, iPad, or iPod touch ready for service

Regards

Giulio

back up my iphone

god70 wrote:

back up my iphone

How to back up your iPhone, iPad, and iPod touch - Apple Support.