So you need to know not only what is officially required, but also what is required in actual practice. There are routine ones, like tetanus, polio and flu which you really should be up to date on whether you are traveling or not. Then there are special ones like yellow fever, cholera, rabies, etc. which depend on your risk of exposure when you travel. And herein lies the rub. What is recommended for any given locale may vary tremendously from person to person, and depending on what has happened in that locale lately.
Vaccines vary tremendously in efficacy.
Even highly effective vaccines may be so expensive or have such risks of side effects that they are not worth getting in all but high-risk situations. The newer rabies vaccines are excellent examples. Also, new vaccines are becoming available at a rapid pace, so what was true last year or even six months ago may no longer be true now. You can save yourself a lot of trouble by keeping your routine immunizations up to date at all times. Then, when you travel, see the appropriate travel medicine specialist at least two months in advance for the special immunizations you need.