As you can see, that situation’s been rectified now, both because I don’t save messages as much anymore and because I finally broke down and bought a larger iPhone. Go me! But at the time, I had tons of old conversations that I really wanted to keep for sentimental reasons. If you’ve got the same problem, then there’s a third-party app that you should keep in mind—Ecamm’s PhoneView.
Behind this funny little icon is a whole lot of power. Not only can you export messages to PDF (as I’ll be demonstrating), but you can save out voicemails as audio files, for example, or export certain app data, your call logs, or your notes. To get started, just download the app from the website I linked above and plug your phone into your Mac using your USB-to-Lightning cable. Once you do, PhoneView will start analyzing your device, and when it’s done, you’ll be able to click on all of the data types you can interact with.
In the case of messages, you can click on a conversation (or multiple conversations) from within PhoneView and choose File > Save as PDF.
Within the document that’ll be created, you’ll have all sorts of useful info, such as the date and time texts were sent.
When you’re satisfied that all of the messages you need are safely tucked away as PDFs, you can feel free to either delete them from your phone or set them to start expiring after an appropriate amount of time (Settings > Messages > Message History > Keep Messages).
I find this to be very useful software, especially if you need to interact with the data on your device in a way that iTunes just won’t let you. Ecamm offers a limited trial (with which you can export a few items to try out the program), and when you’re ready to purchase it, PhoneView is $29.95 and includes free lifetime updates. I mean, you’d kinda think this functionality would be something Apple would provide, wouldn’t you? But I’m happy Ecamm is there to fill in the gaps.