You can look at factors like the processing speed or RAM when researching used iPhones, but how much does that really tell you about the phone's actual performance?
One of the metrics is Geebench's Performance benchmark, which enables all iOS devices to be compared directly against each other. The results, from highest to lowest performance, are as follows:
The iPhone 11 Pro Max costs 1,330 dollars
The iPhone 11 costs 1,280 dollars
The iPhone XS Max costs 1,110 dollars
The iPhone XR costs 1,108 dollars
922 - iPhone 8
742 - iPhone 7
542 for iPhone 6S
There are 308 iPhone 6s in the world
It is also important to compare iPhone models based on battery life. AnandTech's review specialists compared the battery life of each iPhone model over the past few years. Their comparison was based on how long a phone could use a full charge over WiFi.
The iPhone 11 Pro Max has a battery life of 15.58 hours
The iPhone 11 has been running for 14.03 hours
The iPhone XR has a battery life of 12.95 hours
The iPhone 8 Plus lasts 11.83 hours
10.31 hours on iPhone XS Max
9.22 hours on iPhone 7
Battery life and performance tend to follow linear trends. New models tend to be more powerful than their predecessors and have new features that preserve and extend their battery life.
It's important to remember that newer models, regardless of their capacity below 100%, tend to have longer battery life than their older counterparts.