I'm afraid the premise of the question is mistaken. No dictator, including JC, exceeded their appointed term.

The traditional term was 6 months, and it stayed that way until Sulla became dictator in the aftermath of his civil war with Marius. Sulla asked to be appointed Dictator not for a specific term, but with a specific brief - dictator legibus faciendis et reipublicae constituendae causa ("dictator for the making of laws and for the settling of the constitution"). Presumably this office would have expired when the making of laws and settling the constitution was done. In fact, Sulla seems to have resigned this commission within 6 months, conforming to the traditional term.

The office of the dictatorship wasn't used again until 49, when JC held the dictatorship to conduct the elections for 48, since both consuls (who were on Pompey's side) were absent from Rome. He held that office for only 11 days.

He managed Rome in 48 only as consul. After Pharsalus, late that year, he was elected dictator again. The term of this dictatorship is unclear; we know he was dictator again in 47, but whether this is the same dictatorship or a 3rd has been disputed. Broughton, Roman Republican Magistrates, thinks it's the 3rd based on some coins issued by Caesar in 47 that don't carry the title dictator, if I understand his note correctly (It's nearly 5 AM here and I haven't been sleeping, so I may not have all my faculties working. Thank god my school is closed today).

In April 46, Caesar was named dictator for ten years. That is a novel use of the office, but given Sulla's precedent, seems entirely legal.

Caesar's final dictatorship is often called "dictator for life" but that's wrong. Like Sulla's, it came without a time limit but with a brief: Dictator Perpetuus - "Dictator for as long as necessary." Presumably, as with Sulla's office, this one would expire when it wasn't necessary. Who decided whether it is necessary is an open question, and moot, since the Ides of March happened.

The dictatorship was never used after Caesar. So bottom line: no Roman dictator exceeded their term of office, though the office did go through some revisions in the later years of the Republic.

Hey there,

Just to let you know, your question is fine, and we're letting it stand. However, you should be aware that questions framed as 'Why didn't X do Y' relatively often don't get an answer that meets our standards (in our experience as moderators). There are a few reasons for this. Firstly, it often can be difficult to prove the counterfactual: historians know much more about what happened than what might have happened. Secondly, 'why didn't X do Y' questions are sometimes phrased in an ahistorical way. It's worth remembering that people in the past couldn't see into the future, and they generally didn't have all the information we now have about their situations; things that look obvious now didn't necessarily look that way at the time.

If you end up not getting a response after a day or two, consider asking a new question focusing instead on why what happened did happen (rather than why what didn't happen didn't happen) - this kind of question is more likely to get a response in our experience. Hope this helps!