But what happens if you lose your phone, move to a different phone, or are stranded somewhere without your phone (yikes) and need to be able to look up your phone numbers. That's when you realize just how important it is to have them not only backed up, but easily accessible.
So how do you do that?
Click on the Info tab at the top and there is an option to Sync Contacts. If you are on a Mac, this will import all of your contacts into Address Book which is Apple's program on your Mac for managing contacts (if you're not on a Mac, I have no idea where they go, perhaps someone can tell me!). Now your phone contacts are visible on your computer and any changes you make will be sync'd back to your phone.
Android Contacts (People)
Here's where it gets interesting. If you select the Accounts from within People there's an option to Auto-sync app data. This is useful because if you have other apps that have contact information such as Facebook or Skype, People will integrate that information. What this means in reality is that your friends on Facebook will appear in your People display. What really confused me is that you can then get multiple copies of the same person, one from Facebook and another from Google Contacts. If you try to edit the Facebook contact to add the telephone number, it won't let you. That was REALLY frustrating until I figured it out. My solution (and this is just me) is to ONLY display my Google contacts since these are what get sync'd online. To do this, select Google from within Contacts to Display in People. Now the duplicates disappear. If you add a contact that you have as a friend in Facebook, then Android warns you and asks if you want to combine them. This is the work-around for not being able to edit the Facebook contacts.
In summary, it's very important to backup your contacts and have them available online in case of an emergency. Even though it took me a while to figure out the Android People apps, I prefer it over the iPhone contacts because of its tight integration with Google Contacts which I find very easy to use and very convenient. But as I've said before, that's just me.
Note: All references are for Andoid 4.1.1 (Jelly Bean) and iOS v6.0