Thinking about upgrading to the iPhone 5s?

So I got the iPhone 5 a while ago and I like the new features on the iPhone 5s. Since I signed a 3 year contract with fido, would I be able to buy the phone elsewhere and just put my SIM card in the new phone. Can I do this or do I have to confirm with fido and sign a new contract? I'm currently paying 70 dollars monthly with the iPhone 5 with 2GB data, 100 minutes US/Canada and free messaging. Say basically I just want to buy the phone off of like kijiji or something and simply place my SIM card from the iPhone 5 to the 5s. Will this be a problem?

Personally I would not upgrade to the 5s. I have the 5 also and it doesn't seem like much more comes with the 5s and anything that is new will be even better on the next iPhone that will probably come out before too long.

You should be able to just move your SIM card from the 5 to the 5S, as long as the 5S you get is either unlocked or a Fido 5S.

But the differences between the 5 and 5S are pretty small, mainly somewhat faster and a fingerprint sensor. I don't think that's worth spending hundreds of dollars for if you already have a 5. The major difference is iOS 7, but that's a free upgrade for the 5.

If your contract is up then you could trade it in as its still worth alot.