You should check your windshield wiper fluid level "every six months".
Windshield washer liquid (likewise called windshield wiper liquid, wiper fluid, screen wash) is a liquid for engine vehicles that is utilized in cleaning the windshield with the windshield wiper while the vehicle is being driven.
Windshield washing liquid is a vital piece of keeping up your vehicle. Most commercial windshield cleaners contain methanol, a toxic substance unsafe even in little sums.