Heating oil tanks should be inspected regularly for signs of corrosion, leaks, or damage. While there is no fixed timeline for tank replacement, it is generally recommended to replace older tanks after 15 to 20 years. However, factors such as tank material, maintenance, and local regulations, and tank location can influence the lifespan of a heating oil tank. It is best to consult with a heating professional who can assess the condition of your tank and provide specific recommendations for replacement.