American elected officials have to follow specific standards, and even the rules for former presidents are strict. Some policies ensure the safety of former presidents; others maintain a level of governmental transparency and diplomacy.
Many of the things ex-presidents do are rooted in historical necessity. For instance, when Harry Truman left office in 1953, he and former First Lady Bess Truman were penniless. Lawmakers passed the Former Presidents Act in 1958 to provide for Truman and every POTUS after him. Since then, the act has been revised to include additional guidelines, serving as a rubric for every former commander-in-chief.
After the assassination of John F. Kennedy in 1963, the presidential security detail changed significantly. To ensure their safety, current and former American presidents aren't allowed to drive on open roads. This rule has been on the books since Lyndon Johnson left office, but in 2017, George W. Bush made the fact public when he told Jay Leno.
Even vice presidents must follow the no-driving rule. In 2014, Joe Biden mentioned, "There are a lot of reasons to run for president, but there's one overwhelming reason not to run for president. I like to get that [Corvette] Z06 from zero to 60 in 3.4 seconds."
The Presidential Townhouse is adjacent to the White House. In 1969, Richard Nixon designated it as the official lodging for former presidents visiting Washington, DC. The home has five stories, several bedrooms, two dining rooms, and accommodations for the Secret Service.
A support fund covers the cost of maintaining the townhouse.
Former presidents still have civic duties to uphold after their time in office. Namely, they're supposed to travel. To encourage ex-presidents to continue serving as goodwill ambassadors for the nation, the government offers them a $1 million annual travel budget.
Presidential spouses receive $500,000 in yearly travel allowances. Former presidents also have diplomatic passports for life, allowing them to bypass the hassle of obtaining visas for different countries.
Former presidents still receive national security briefings, although they aren't given updates as often as the sitting POTUS. This allows ex-presidents to advise members of Congress and the current commander-in-chief in times of national crisis.
Bill Clinton declined security briefings when his wife Hillary Clinton was Secretary of State. He wanted to comment more freely on national and international issues.