Don’t confuse backing up your Device (iPhone, iPad) with separately backing up your Contacts.

An iTunes backup will backup ALL data and APPS stored on your device and usually writes that backup file locally on your laptop or iMac. The problem then becomes ‘What to do if I don’t have enough space on my drive?’.

If you enable iCloud Backup, it’s automatically backed up or you can force it to backup on demand. The default level of storage might not be enough, but it’s only .99 cents a month to get 50 gigabytes of iCloud storage.

I still use the backup contacts app to remove dupes, keeping a fresh backup available on my email since I’m more likely to need JUST my contacts restored and NOT my entire iPhone.