A state-of-the-art watch circuit (oscillator and counters, without
display) consumes around 80nA. To drive an LCD display you need
Guess the battery's self-discharge is still dominant, so an always-on
display does not shorten the battery lifetime.
Early digital watches (e.g., Clive Sinclair's "Black Watch" kit) used
a red LED readout. LEDs were/are power hogs so the watch had a button
to press for display. At uni I had an evening economics class where the
lecturer wore such a watch. After pressing the button and glancing at
his watch, there would be an arc of brilliant ruby red traced out amid
the gloom of the dingy theatre as he swung his arm back to his side
before the display timer shut itself down.
Avoid using the backlighting and alarm if you wish to extend cell life.