Petit jurors are on call for approximately one month, but they will most likely not be needed every day during that month.

"On call" means that prospective jurors will not be asked to report to the courthouse unless their names are randomly selected to report for jury selection. But jurors are expected to be available throughout the term of their service and to report when the court instructs them.

Grand jurors serve for 18 months, convening once a month for 1 to 5 days.