Visas for many countries have an associated "maximum stay" (for example, the visa is valid for a maximum stay of 90 days). For those visas, how are the days counted, or does it vary based on country? Does the stay begin on the partial day that the traveler arrives or the first full day spent in the country. Does it end on the last full day spent in the country, or the actual day the traveler departs?
For example, if a hypothetical visa has a maximum stay of 15 days and the traveler arrives in country on the evening of the 1st, what is the last day he can leave?