Newer vehicles use long-life radiator coolant that is specially formulated to last up to 150,000 miles or five years in-between changes. You still need to check the system as neglecting the cooling system is not a good idea. According to the US Department of Transportation, the leading cause of mechanical breakdowns on the highway is attributed to cooling system failure.
NOTE: If you have an older vehicle that used conventional antifreeze in the cooling system, be aware that this fluid needs to be changed every two years or 30,000 miles instead of the new five-year standard. This replaces the corrosion inhibitors that get depleted.
By checking the coolant level, including the strength and condition on a regular basis, you will know early if there is a problem. This will also help to minimize the risk of overheating and the many other possible problems caused by worn-out or diluted coolant.
Regardless of how new or old the coolant is, leaks can happen any time. Usually but not always, if the coolant is low, the system has a leak. The hoses, gaskets and seals are particularly bad for leakage as they age. The radiator and heater core have similar problems. Any leak needs to be found and fixed as soon as possible.
Just because your coolant light comes on, that doesn't mean you have a leak. There can be many possibilities. The first thing to do would be to check if your coolant is actually low.