Mr Deby took power in a coup in 1990 and later introduced elections.
A referendum in 2005 scrapped a clause restricting presidents to two terms, but Mr Deby said that if he gets re-elected he will reinstate it.
In the last year, Burundi, Rwanda and Congo-Brazzaville have all changed their constitutions to allow their presidents to run for office again.
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Mr Deby said on Tuesday that reinstating term limits would provide "vitality" to the democracy.
"We must limit terms, we must not concentrate on a system in which a change in power becomes difficult," he told the ruling party.
"In 2005 the constitutional reform was conducted in a context where the life of the nation was in danger," he added.
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Chad's President Idriss Deby has announced he will run for a fifth term in April's elections.