Memory, carrier, camera features, and processing power all rank highly when considering a new smartphone. Interestingly, carrier options are a priority for ages 35 to 55 while ages 18 to 24 turn towards camera features and picture quality.
https://www.notebookcheck.net/MediaTek-study-finds-long-battery-life-to-be-the-most-important-feature-for-smartphones.346911.0.html