Back Up Your iPhone. Please.

BACKING UP TO ICLOUD

Backing up your device is the most important thing you can do to recover 100% of your phone's data, including Contacts, Calendars, Reminders, and all of your Apps. Do NOT back up photos/videos to iCloud, as you will fill up your iCloud storage. I'll give tips for backing up photos and videos here.

Settings > Apple ID > iCloud (Toggle off Photos)

Tuvy Guss