Apple recommends in their guidelines a minimum tappable area size of 44x44 points for all controls. A lot of times this can be corrected in an app without changing how it looks, but making it objectively easier to interact with for everyone.

Two versions of the same music app. The first one has buttons with small bounding boxes that are less than 44 by 44 points. The second one has managed for the app to look the same but for the bounding boxes to be more than 44 by 44 points. The apps looks the same but the one with bigger touch target areas is a better experience for everyone.