i don't know about you, but I have a S3 with 16GB and a 32GB card.
Effectively that means I have approx 11.3GB on the phone as 4.7GB is taken for the ROM and Phone storage.
Now 12GB isn't a lot of space (which is why I would never consider the Nexus 4) - my media on my external SD card alone is around 12GB - approx 6GB of music and 6GB of videos and then a GB or so of Books.
So really when considering a new phone (especially if there is no SD card you really need a 32GB phone minimum).
Saying that I freaked out last night when I realized I only have 0.5GB left on the phone - I know I have a lot of apps, but I don't have that many.
In case you don't know you can check this by going from the home screen. Menu - System Settings - Storage. It takes a while but it will eventually populate the categories.
Turns out I had 8GB in Apps, 2GB in Media and 1.5GB in Misc.
I really wasn't expecting this, they were all a lot higher than expected.
To check apps is easy - press on the Application bar and it takes you to the application manager - All tab, and sorts by Size rather than name.
Main culprit were the GTA apps - I had pushed them to the card, but not sure if latest update recognized that as all together both apps were around 4GB - uninstalled them for the moment - will reinstall at a later date - wasn't playing them anyway. My next highest was magazines - I had subscribed to a regular free weekly - and it was downloading them for me - I hadn't read any of 8 downloaded and each was approx 100MB. Read and then archived or deleted them - Magazine down to reasonable limits now. And my app bar is now at 4.3GB much better.
Media (what I call Pictures, videos) - when you press on the bar you just get the gallery app which of course is worthless. Actually more than worseless...... as it pulls in everything and anything. Especially as all my pics are saved to the Ext Sd Card - where there is approx 1GB - but I know there isn't anything like that on my phone.
I ended up using my file explorer - ES File Explorer - multi-selecting folders and checking properties. Bingo when I included the DCIM folder on the phone. So I popped in there and hey presto I have two thumbnail files, one at a GB and another at 0.3GB - found my problem and deleted them (also tried to check Gallery to stop it, but no option there, Tried QuickPic my preferred gallery viewer and disabled the pre-caching options - will check another time to see if they caused them).
Problem solved and another 1.3GB freed up.
Miscellaneous files - was around 1.8GB - so pressed on bar and went in. Most of the culprits are listed - my main ones were FMH2013_data (drat why is it saving here - but nothing can do about it - and need this so no deleting it) - Carbon backup (not sure why here, but will do another backup sometime this week and delete this one) - GReader 0.8GB (ahhhh -so that is what they mean by ext card - its actually the phone SD card - so changed some settings to delete the cache once read). So another approx 1GB freed up, as I also deleted the caches of some old apps that I had uninstalled, which had not removed their caches on uninstallation....
Net result is I now have 5GB of free space on my phone.
If you haven't checked yours lately I would suggest that you do so, I know I am going to add this to my monthly maintenance...... as that really caught me by surprise.