It doesn't really make much difference ! The speed of technological development means that - most mobile phones are obsolete before they get to the retailers !
An IPhone 7
The first iPhone was bulit on January 9, 2007.
Depends on which iPhone you buy. iPhone 5s comes with 16 or 32GB of storage. iPhone 6 & 6 Plus comes with 16 or 64GB of storage iPhone 6s & 6s Plus comes with 16GB, 64GB, or 128GB of storage.
iPhone 6s plus
IPhone 7s are more supirior
Plus 3T
I bought two cases from this website: chicleader.com They are great with affordable prices. And the delivery time is ok.
The Apple iPhone 6 Plus has a better battery life than the Apple iPhone 6.
It's your phone - only you know that information !
You can check the model number on the back of the phone or in the settings menu to determine if you have an iPhone 6 or 6s. Additionally, the iPhone 6s introduced 3D Touch technology, which the iPhone 6 does not have.
iPhone 6s comes in two storage variants which are 32GB and 128GB.
Yes, iPhone 6 and 6s are interchangeable as far as cases go.