Given the warm-up requirement even for LCD panel displays, it makes sense both for calibration purposes and for general working to disable anything that turns the screen off too quickly. Ambient lighting: Changing the luminance (brightness) on a calibrated display to allow for changes in lighting conditions will invalidate your calibration. Aim to achieve consistent lighting instead.
Some display calibration and profiling tools (and some displays) offer ambient light adjustment options that are intended to compensate for changes in the lighting environment. These should never be used. Arrange things so that the display is the brightest object in your field of view but don’t work in a completely dark room.