Moses served not only as the people’s judge, but as their rabbi as well.
Even without all the quarrels and disputes and even without all the monetary cases, it still would have been impossible for him to answer all of the people’s halakhic questions.
Almost everyone has something to ask: whether a pot can be used for meat or for milk; whether a certain activity is prohibited or permitted on Shabbat; whether the text of a mezuza was written properly, etc.
Even if one were to sit down to answer these questions day and night, it would not suffice.
There is a story about the daughter of the rabbi of a small community who, upon getting married, requested that a condition be added to the ketubba stating that her husband would not serve as a rabbi.
Because in her father’s home, from early in the morning until the middle of the night, there were always people around, and she did not want to go on living that way.
–Rabbi Adin Steinsaltz