This is a test of commonsense. Complete the next sentence:

How to decide whether to buy a newer or older iphone
Decide whether you want all the new features.
If you really care about the new features, you might consider a newer model iphone. If you don't really care about the new features, older models will be right for you at a good price.
Find out if it's affordable, and the phone is worth at what you want? If you want all the new features offered by the newer models, you have to make sure you can afford it. If you can afford it and want the new features, it will be worth it.