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.
A President may serve no more than two terms. Each Presidential term is four years. The maximum number of years a President can serve is 10.
The President of the United States of America can be elected to no more than two four-year terms, for a total of 8 years. However, if a person fills in a partial term that another was elected to, if that partial term was no more than 2 years, he can still serve two more complete terms for a total of 10 years, but if he has already served more than two years, he can serve only one more additional term.
These restrictions are imposed by Section 1 of the 22nd Amendment to the U.S. Constitution. Other applicable areas of law concerning presidential succession are set forth in Article I, Section 1, Clause 6 of the Constitution, and by the 25th Amendment (see Related links, below, for more information). The law is virtually silent on the improbable, but possible, event that a person who has previously served for the maximum ten years in the circumstances described above is subsequently elected, or becomes after appointment by the President, Vice President - and becomes thereafter President upon the death, incapacitation, or resignation of the elected or serving President; in such a sequence of events, a person could presumably serve as many as 14 years - or even more, in the even-more unlikely event that the scenario described should occur more than once.
Of the "recent" Vice Presidents who assumed the Presidency after the death or resignation of their predecessors, President Lyndon B. Johnson ("LBJ") was allowed by law to be elected to 2 terms on his own (although he declined to run a second time after being elected in 1964), while President Gerald R. Ford could only be elected to one more term, as LBJ had served less than 2 years of President John F. Kennedy ("JFK")'s term after JFK was assassinated, while Ford had served more than 2 years of President Richard M. Nixon's second term after Nixon's resignation..
If you mean presidents of the USA they can serve two four year terms. So that makes 8 years altogether.
Presidents of companies would differ depending on the rules of the companies.
Presidents of other countries would also have different rules governing them.
The president serves in office for 4 years per term, for up to 2 terms, unless they are impeached, die, or killed. The term limit was imposed after FDR's 4 term, 12+ year presidency.
Under the 22nd Amendment:
The US President can serve only two elected terms of 4 years each, as well as up to 2 years as successor to a President who dies or otherwise leaves office. This creates a practical maximum of 8 years and a potential maximum of 10 years.
The president serves for 4 years, or 8 if re-elected.
A US president may serve up to two terms of four years each, for a total maximum of 8 years in office.
A president is elected to serve a term of 4 years and can be reelected again for 4 more years for a maximum total of 8 years.
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6 years
8
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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
4
Five
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8 years
the president serve for four years in the united states.
The president can serve up to eight years, which is two terms. A term is four years. A limit has been set, so our government will not become a dictatorship.