This depends on the country you are referring to.
The list below shows all the continents and countries both in alphabetical and unbiased order, with presidents and how long they can serve.
Countries with monarchies do not have presidents, they have Prime Ministers instead. Countries who do not use "Presidents" are not listed below.
African Continent
Asian Continent
European Continent
Oceania Continent
North-American Continent
South-American Continent
Countries with Prime Ministers - Prime Ministers serve unlimited four or five-year terms depending on country. The same applies to countries with Govenor-Generals. In countries that are a British Commonwealth (Australia, Canada, etc) the British Monarch can dismiss (fire) a head of office or extend their stay if necessary.
many
4 years
A president can serve two presidential terms of four years. Altogether, he/she can serve eight years as president.
6 years
ten years
8
8
Five
4
8 years
the president serve for four years in the united states.
The term is 4 years . A president can serve at most two.