Backing up your data can help prevent a devastating loss of your valuable and precious information. If your device is lost, stolen, or simply stops working and you have not been faithful in backing it up, you could lose your data, photos, contacts, etc. Apple provides two ways to back up IOS devices. The first is to use iCloud, but frequently this will require paying money to Apple to increase your iCloud storage. They only provide 5 GB of free storage and that is used up pretty quickly, especially if you have newer device with 128 GB of storage. Granted, for $1/month you can get a more reasonable amount of 50 GB, but some are still reluctant to use this option. The second option is to use your Mac to do the backups. This requires you have enough storage capacity on your Mac but so long as you do there is no additional cost, and your data stays on your device.
The article below discusses using your Mac to back up your IOS device. How you choose to back up your data is up to use but it is strongly recommended that you do so one way or the other. Or, if you are paranoid like me, you can use both ways.