Whether or not you use the Noise app as a watch face complication, it continuously samples noise levels to give you real-time feedback, and some users have reported noticeable battery drain with the feature enabled.

Does Compass complication drain battery Apple Watch?

Since the compass uses your Location Services, it can have some affect on your battery. When you open Compass for the first time, it requests permission to access your location. Tap While Using the App to grant permission.

Does walkie talkie mode drain battery?

With Walkie-Talkie, you essentially are starting a real-time audio channel with somebody who just happens to be muted by default until you hit the PTT button. That means that it may drain more battery than just slinging voice memos at each other.