how many gb's do i need for iPhone5

Since the iPhone's storage cannot be increased, buy as much as you can afford. Better to have and not need than need and not have. Plus it will be worth more when you sell it.

If your a casual user who only needs a few apps and games, and not 1000s of songs and pics, go for 16GB. IMO that is more than enough for most people.. I hav 1000 pics, 200 songs, 15 apps and still hav around 6GB left.. If you can afford 32GB though then why not 🙂