I open the hood every 5000km and just before and after service to monitor only. My car 178k km ad but never topup myself because service center will topup for me. The amount of water drop and fuild drop very2 litle only la if your car in good condition. No need to paranoid to check everyday.

Service center use tap water only to mix with coolant. No need to use distilled water because the coolant itself act as antirust.