Using your G - Shock GA110CD - 1A2 is easy. Simply press the buttons on the side to access different functions like setting the time, date, and other features. For daily use, you can wear it anywhere as it's shock and magnetic resistant and has 200 - meter water resistance, so it's okay to get it wet in the shower or light rain. When it comes to battery replacement, after about 2 years, you'll need to get a new CR1220 battery. You can have it replaced at a professional watch repair shop. To keep your watch looking good, clean it regularly with a soft, dry cloth. Avoid exposing it to extreme temperatures or harsh chemicals as this may damage the resin case, bezel, and band.