Longer stays generally equate to an increased risk to the traveller as they are exposed to risks for a longer period. The duration of a trip may influence the choice of antimalarial, for example the maximum licensed duration of treatment with Lariam®. 

Long stays will increase the individual's exposure to health risks. Extended stays may also result in a change in the risk of specific diseases as the seasons change.

There is also a risk that an experienced or extended traveller will become complacent with the potential health risks and take fewer precautions or be less diligent with preventative measures. It is important to advise travellers planning an extended trip, that the risk factors will be continual during the trip; they will not develop immunity or incur lower risk.

It is equally important to ensure travellers staying for short periods of time are not complacent about the risks because of the short period of exposure. It is just as likely that a traveller will be bitten by a mosquito carrying malaria or consume contaminated food or water on the first day of a holiday as the last, and as a consequence, preventative measures are equally important at all times during the trip.

In some situations it may be necessary to receive specific vaccines and have a certificate confirming vaccination, to enable travel between countries. This is currently applicable to travellers leaving countries where yellow fever is endemic and for countries that have been shown to "export" wild poliomyelitis infection (currently Afghanistan, Nigeria and Pakistan). Travellers to Saudi Arabia for Hajj or Umrah must present proof of meningitis vaccination.