Well the question is not as simple to answer as you think. There are many things you need to take in to consideration, not only price or good look.
We all know this amazing feeling when you buy a brand new device. The first start, changing all settings to best fill our needs is really good, but does paying more money justify this?
Not really, new models don't have as many changes as you think. Most of the time the changes focus on the camera, more memory, or better battery, but when you look closely the price wasn't worth it.
If you don't take hundred pictures with your phone and play the newest games, the changes are not needed. Your current device is still very good. You can still use it to play games, make good pictures, or use the internet.
The little improvements that come with a one year device are not that big.
The situation is different when you have a contract device however, you pay the same amount of money. but you get a new device without extra payment, so go for it. Why not, you not only get a brand new device, but you can earn money by selling the old one.
In any other case when you need to pay a huge amount of money, for a very similar device it is not worth it. Your one year old device is more than enough right now.
We hope that this short text will help you save some money as well as help you enjoy your device more.