Do gas stations have to unload oil every day?

Yes.

Generally, gas stations will receive and unload fuel after ten o'clock in the morning, or at five or six o'clock in the afternoon, but few gas stations wait until the tank is empty before filling in, which will affect the refueling of the vehicle. Affect gas station sales.

Gas stations refer to refill stations that serve cars and other motor vehicles and retail gasoline and engine oil. They generally add fuel oil, lubricants, etc.