I've been to Bali over 30 times and in the early days used to get the combined typhoid/cholera needle. I stopped doing it years ago as I didn't think I needed it. I am always very vigilant, never clean my teeth with tap water, take anti bacterial hand wash, watch what I eat etc etc. I arrived home last week and have been very sick, just diagnosed with two notifiable diseases one being typhoid. I will definitely be having the vaccine when I am better. They now last for three years. It doesn't matter how careful you are it can happen