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I see something on the iphone about backing up Camera Roll. That's all ... no idea why I should want to do that. email storage is virtually nothing.
No idea what should be backed up from the iphone, for that matter.
I signed up for Dropbox last week. I think that will act like a global backup without costing a dime. What do you think? I also understand that I can install Dropbox to the iphone. I am not quite sure of this as it is like pulling teeth to ask the Dropbox crowd and get any answer at all.
What I personally like about iCloud and backing up to it is that if my phone stops working, breaks, or is stolen, I can walk into an Apple retail store, pick up a new iPhone, and immediately (relatively speaking) have that new phone be essentially identical to my previous one. Certain passwords notwithstanding, all of my contact info is there, my text messages, my photos, my apps, etc.
In general, iCloud will back up pretty much everything on your phone, including any data associated with the apps you have, both stock & 3rd party. However, not all of the data that's backed up counts against your iCloud storage allotment.
For example, your text conversations in the Messages app and your contact info in the Contacts app will be backed up but don't count against your free 5 GB limit.
On the other hand, the photos & videos in your Camera Roll in the Photos app
do count against your limit so you'll need to make sure you have a plan for how those are handled.
Regarding Dropbox, I believe the current offer of free storage for new accounts is 2 GB. If so, then you're already at less than half the storage of iCloud if you choose to use Dropbox instead of iCloud so that doesn't really make sense to me. Also, Dropbox can't back up data from stock iOS apps (e.g. Message, Contacts) as far as I know so, to me, it immediately loses value as an exclusive backup option. Maybe that's not what you meant when you mentioned Dropbox but I'd make sure to understand what it can do compared with iCloud in addition to what it can't do.
To download the Dropbox app for your iPhone, see below:
https://itunes.apple.com/us/app/dropbox/id327630330?mt=8
As I said previously, I recommend simply purchasing more iCloud storage if you can as that's the easiest route in terms of backing up your iPhone. For more info on that and on iCloud in general, see the links below from the Apple Support site:
iCloud: Managing your iCloud storage
iCloud: Storage upgrades and downgrades