Congress provided for lifetime protection for former presidents and vice presidents in 1965, changed it to 10 years in 1994, and reinstated it to lifetime protection in 2013.
In 1965, Congress authorized the Secret Service (Public Law 89-186) to protect a former president and his/her spouse during their lifetime, unless they decline protection.
In 1994, as a cost-saving measure, Congress acted to limit protection for future former presidents and spouses to just ten years after they left office.
In 2013, Congress passed, and President Obama signed, a new law restoring lifetime protection for all former U.S. presidents and first ladies. The law passed with widespread bipartisan support, the House passed the bill by voice vote and it was passed by unanimous consent in the Senate.