The 36 hour battery life also isn't a best-case scenario. According to apple.com
"All-day battery life is based on the following use: 90 time checks, 90 notifications, 45 minutes of app use, and a 60-minute workout with music playback from Apple Watch via Bluetooth, over the course of 18 hours;"
"All-day battery life is based on the following use: 90 time checks, 90 notifications, 45 minutes of app use, and a 60-minute workout with music playback from Apple Watch via Bluetooth, over the course of 18 hours;"