Connecting your iPhone to your machine seems to be the most obvious task normally. You can sync your data to iTunes and make a backup.
When you get a New machine you Will probably transfer content from your old one and along comes the iPhone archive.
But what if your old machines hard drive crashed taking along all the data with no backup?
Or even worse, what if your computer was stolen?
The last case happened to me lately. All my data gone and among that was my iPhone backup data. I got a New machine, but my iPhone just did not want to get along with that. Every time I wanted to sync it via iTunes it wanted to delete everything on my iPhone.
I’m pretty sure there are more efficient/cheaper workflows out there but mine went as follows:
1. Connect your phone to your machine
2. You have to get images, music, audiobooks etc. out of your iPhone.
I used a software called phoneView which cost me about 20$.
This software enabled me to restore images to my iPhoto and the rest of stuff to my iTunes library.
3. You need to get your Apps out of the iPhone. For this you need to log in to iTunes store.
4. Select Store>Authorize Computer… insert your app store user and password and click Authorize.
5. Right click on the phone icon in iTunes on the left side and select Reset Warnings
5. Right click on the phone icon in iTunes and select Transfer purchases…
6. I tunes might ask you to insert your AppStore password again.
7. Now wait. It took a long time to sync 6 pages of apps in my phone.
After these steps your iphone apps will probably be scrambled. Reorder them as you like.
Once this is done you’ll have to recheck which photos, audio content, videos etc. you want to sync, but that’s a standard procedure really.
I hope it helps.