Vaccination needs split into two lists: what is legally required and what is medically wise. The mandatory list is short for most destinations. Yellow fever certification is required by many countries in Africa and South America, or if you arrive from a country where the disease circulates, and proof of polio or meningitis vaccination applies for a few destinations, notably meningitis for pilgrims traveling to Saudi Arabia. Requirements are checked at the border, so this is one document worth carrying in paper form.
The recommended list is longer and depends on region, season, trip length and what you will be doing. Hepatitis A and typhoid come up for most of Asia, Africa and Latin America; hepatitis B, rabies and Japanese encephalitis for longer stays or rural travel; and routine boosters like tetanus and measles should be current everywhere. Malaria has no vaccine for travelers in most cases but may call for preventive tablets.
The right move is a travel clinic appointment four to six weeks before departure, since some vaccines need multiple doses or time to take effect. Cross-check with your government's official travel health site and the destination's embassy page, as entry rules do change.