MagSafe support
Most but not all iPhone 17 Series cases have MagSafe support (the metal ring built into the case). I generally encourage people to make sure they get a MagSafe-enabled case because of the number of MagSafe accessories on the market, some of them quite useful. In the past, you could $5-$10 by getting a case that leaves off the Magsafe ring, but, as I said, the vast majority of iPhone 17 Series cases are MagSafe-enabled.
Thickness
Some people like minimal cases that add little to no bulk to their iPhones, but the majority of people are looking for a case that offers good protection — or even maximum protection. I tell people to find a case that’s not too thick — and maybe even pretty slim — that offers at least 6-foot drop protection (and good corner protection).
Clear case
Clear cases are popular because they show off your phone (and its color). Clear cases, especially cheaper ones, can become less clear over time and slowly start to yellow. Many case makers now add UV protection to their clear cases to prevent yellowing.
