Before you get on the plane you know that there are already a whole bunch of things that need doing first. The most common question that people ask is about vaccinations, which ones are required, which ones are recommended and which ones are not entirely necessary.
The answer is different for different people and will end up with what you feel comfortable with. Many people have lived for years in Bali and Indonesia without ever having a single vaccination or a single problem related to not having one. Your health is important and if you feel that you are better safe than sorry then you should start your vaccination regimen at least a month before departing.