Are American workers less likely to observe a religious holiday now than they were 30 years ago? In this paper I use evidence from religious holidays to explore the evolution of market hours' flexibility and religious observance during the last thirty years. To do so, I take advantage of three different sources of exogenous variation: the first is the timing of the Current Population Survey, which allows me to observe data that is collected during different holidays in different years. The second is the timing of the religious holiday, as most are scheduled either with the lunar or the solar calendar. The third is the required observance of the holiday: in some holidays believers are called to abstain from work (Yom Kippur), in other holidays not (Tu b'Shevat), some holidays have been secularized (Saint Patrick's Day), and other holidays not (Good Friday). Additionally, I differentiate between any changes in hours of work during religious holidays across time and changes across cohorts. My results suggest that work schedules' flexibility has changed little during the sample period, yet less people are taking time off from work during Good Friday, while more people take time off from work during Yom Kippur, Rosh Hashanah, Mardigras and Saint Patrick's Day. These results are consistent with the increasing secularization of Christians in America, the Baal Teshuva movement among Jewish Americans, and the commercialization of Mardigras or Saint Patrick's Day. These results suggest a change in which holidays workers choose to observe.