With normal circumstances, it is not required to change the coolant with Coolant Replacement Sg frequently. You only need to change it when you find any leak in the cooling system of your vehicle. Your vehicle tells you about the hotness of engine with overheating issues or over hotness as compared to usual stage. In this case it is very evident for you to repair the cooling system or keep topping up but not on frequent basis as this thing can mix the old & new coolant that is not the ideal solution.