Answer:
My life can be measured in hours. I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
i'm popular for Knuzlocks what am i
My first keeps time, my second spends time, my whole tells time.
Sleeping during the day, I hide away. Watchful through the night, I open at dawn's light. But only for the briefest time, do I shine. And then I hide away. And sleep through the day.
You throw me out when you want to use me and you take me in when you don't want to use me. Who am I?
What never gets any wetter no matter how hard it rains?