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I bought a 16GB phone around 15 months ago. I thought 16GB would be plenty (it always was in the past, and I don't consider myself a "power user"), but here's where I am today:

Songs: 377
Videos: 17
Photos: 667
Applications: 51
Capacity: 12.6 GB
Available: 152 MB

i.e., I'm maxed out.

Going into the "Storage" menu: "Music" is taking up 2.1 GB, and "Photos & Camera" using 1.9 GB. At some point, I will offload all the pics/videos to the computer and start fresh; but they're almost all of our kid, and I like having them on the phone. (I upload the best ones to Flickr, but retain the originals.)

As for Music -- our iTunes library is so vast, I feel like I should have either no music on the phone at all, or like 10 GB worth. This "middle ground" -- picking/choosing just a few random artists to conserve space -- feels like it misses the point of synching with iTunes.

Bottom line: I would never go with 16 GB again. The iOS 8 update was a PITA. And as others have pointed out, software is only getting bigger...
 
I wouldn't recommend the 16, especially on the 6 plus. You'll want to use it for much more with the big screen real estate. I have the 64 and this phone is the first phone that I really use as an extension of my PC so I need all the space for apps. It's the first iphone that I felt had enough to it. I'll even use it for presentations and training at work rather than dragging my laptop around - plug in with HDMI. I have an Airstash that I plug into my PC and save all my files, then I can access them from another PC, iPad or my Plus via the Airstash wifi. It's actually pretty cool as with my iPhone and Airstash I pretty much have everything at my fingertips even in a power outage or in a no cellular service area. Now do I create presentations or spreadsheets on my Plus - heck no, but am able to access to make changes or use anywhere I need it, when I need it.

If the 16 still makes sense for you, I totally recommend the Airstash for additional file, photo, music, storage. You can set it up with whatever size SD storage that makes sense for you and can use it with more than just the iphone. Great way to manage the storage between devices and for any device where storage might be low.
 
I'm using the 16gb iphone 6 plus.

DropBox used to hold pictures to help with space and more importantly to make sure my pictures are safe if something happened to my phone.

I've used 5.6 Gb with 6.2 Gb remaining.

Applications 34

Only 21 songs as I use an iPod Touch for music.
 
3 to 4 years before, most phones (including iPhones) started their base model with 8gb. 16 gb and above were considered a luxury then, comparable to our 64gb and 128gb now.

But times have changed now. With most of the media files, apps and software becoming bulkier day by day, a day will come when even 64gb will seem to be just enough and not a luxury.
 
These 16GB RAM threads are all alike. Same predictable replies from both sides of the fence.

This should all be solved one day as I am pretty sure by the iPhone 7 Apple will start with 32 or 64GB. The day will come when even 64GB will be pushing the lower limits of usability.
 
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