I have an iPhone 5 16g do I need to back it up?

I keep getting messages to back up my phone. Any tips on how to do this? Also when done does it free up any memory? One more, does the camera have a zoom? The 3G did but I can't find it on 5.

You can back up your phone through iTunes by connecting your phone to it with the USB wire and set up your iCloud account, It doesn't free up memory it just stores all your contacts and I believe your songs you brought and your pics, your settings etc, I would make sure and see what it actually backs up because that's all I could remember that was backed up on my iPod Touch, I have no idea about the zoom for your phone's camera, it should have it just look for it in your camera's settings and if you can't find it try downloading an app that can zoom in and out for your camera if possible, and besides your phone being 16g gives you enough room for your stuff but if you have loads of pictures, music and apps stored up on your phone then back up your phone and free up some memory for your phone, but be careful when you update or back up your phone because it may sometimes ask you about a setting that was changed or needs to be changed, at that moment be careful what you choose because in the past it had deleted everything off my phone when I clicked the wrong choice, I hope this helps you, I would also call Apple for more information or go back to your phone carrier and ask for help.