How can I back up my app data?

I have some app data that I'd like to preserve when the time for a new iPhone rolls around. This app does not (seem to) have any cloud-syncing functionality. I regularly sync my iPhone to iTunes via USB on a Macbook Air running OS X 10.5.8. How can I ensure that this app's data is backed up, so as to re-use it on a new device?

Solution 1:

If you take a full backup of your iPhone (right click on it in iTunes and choose Back Up) and then restore it to a new phone, all data will be preserved, including apps' data:

iTunes will back up the following information

• Contacts* and Contact Favorites (regularly sync contacts to a computer or cloud service such as iCloud to back them up).
• App Store Application data including in-app purchases (except the Application itself, its tmp and Caches folder).
• Application settings, preferences, and data, including documents.

From iTunes: About iOS backups.

Solution 2:

Vlad's answer is good, and he's absolutely right.

An alternative to iTunes would be to use an iOS device browser. This would be especially good if you only wanted to back up one app's data rather than the whole device. Options of these include Phone Disk and PhoneView.