If you just want to be "preventative" ny all means do all the items other posters said. If you actually check your car, then you will know when its time. Yea there are rads that can last a LONG time and them there are others that get replaced from corrosion, physical damage of they just plain fall apart. You DO need to think about one other thing not addressed here so far: Water wetter is a GREAT product, BUT it doesnt have the corrosion inhibitors and seal lubricants that antifreeze has. Keep your trouble quotient low and fill with antifreeze after you check your radiator and hoses. -SP