How to permanetnly delete everything from iPhone?

I'm preparing to sell my old iPhone 5 for the upcoming iPhone 6. But I don't want anyone to see my private data such as photos, contacts and text messages. Is there an easy to permanently delete the data?

Was my intrusive co-worker rude or just clueless?

Does my co-worker not "get it": that as a junior person, you limit interruptions of more senior people to a bare minimum? She just finished school and just started working. I'm in my 40s.

She constantly stops by people's offices (who are more senior than she is) and yaps about her personal life. Like we care.

On Friday, she called me. We weren't working on anything together so she didn't need to call me, and so I didn't answer the phone. She didn't leave a message.

My firm's email system (affecting desktops and iPhones) wasn't working, so I decided that I could just do my work later, and so I started to leave.

Then as I was leaving the building, as I was literally stepping into the elevator, she came tearing out into the lobby. "Sorry to bother you, but I've been trying to email something to myself, but it doesn't show up on my phone. Do you know what's wrong?"

I said, "It must not be working. Have a good weekend", and then left in the elevator.

What junior person holds up a senior person like that? She must have been calling about her same stupid issue.

Am I right, or am I too sensitive (in which case her etiquette and manners were fine)?

Thanks.

Added (1). To add: the new co-worker is about to get fired because nobody will work with her, and so she doesn't have anything to do. My boss refuses to let me work with her. I don't know if the reason is because she bugs the daylights out of people.

How much does an iPhone 5S from Sprint really cost?

I'm getting an iPhone 5S, 16 GB, Gold from Sprint (yes, they DO have them in stock at the store I'm buying from), and online it says there are two ways to pay…
1.) "EasyPay" ~ Pay $0 down @ the register and pay $26 a month for 24 months.
2.) "2 Year Contract" - For the phone I would normally pay $649 for the phone but with "instant savings", I pay only $149.00 and don't have to pay ANYTHING else for the rest of the 2 years. Does it Really work this way? And can I upgrade whenever I want? Serious, NICE answers ONLY please!

My iPhone started losing battery quickly. What should I do?

A few days ago, my Iphone 4s started losing battery very quickly. Last night it was at 83%, all applications were closed and then this morning it had lost all power and turned off. I already made the 20 changes in Settings that are supposed to use less battery and this is still happening. I think this is an issue with the phone. What should I do?