The government does not stop taxing Social Security benefits after you reach a specific age, such as 70, despite certain internet myths to the contrary.
Until you pass away, all of your Social Security benefits are subject to taxation.
The fact that each state treats Social Security differently is probably the cause of some of the ambiguity surrounding the tax status of Social Security payments.
Many states approach Social Security in a manner similar to how the federal government does, taxing each dollar of it according to the tax rate that your complete retirement income falls into.
This implies that you will pay taxes on your Social Security payment twice: once to the federal government and once to your state.
Social Security is only partly taxed in some states. They may only tax 50% of it or employ some other method to calculate the precise portion of your monthly paycheck that is subject to state taxes.