In general, Orthodox Jews tend to structure their lives around obligations and restrictions called mitzvot, from observing the Sabbath and praying three times a day to making sure their clothes don't include a mix of wool and linen. But a broad spectrum of observance exists among the country's half-million Orthodox Jews, according to the Pew Research Center's 2013 “Portrait of Jewish Americans,” the study every American Jewish journalist is statutorily required to cite at least twice a month.