Hello Mary,
It really depends on how much sharing you do with your data, Dropbox is excellent for sharing family photos or personal and work data.
If you are only worried about being sure your phone is backed up then stick with iCloud.
To automatically back up your device each day, turn on iCloud Backup via Settings > [your name] > iCloud > iCloud Backup and toggle iCloud Backup to on. If you’re using iOS 10.2 or earlier, go to Settings > iCloud > Backup. The device will then back up when your phone is connected to power, locked, and on Wi-Fi.