In practice, when the question is whether it is too late to do a something that must be done "by day," the practice is to follow one of the earlier opinions. When the question is whether it is too early to do something that must be done "by night," the practice is to follow one of the later opinions. For calculating the end of Shabbat or major holidays, the desire not to end Shabbat early, along with the Talmud's description of the end of Shabbat in terms of the appearance of stars in the sky, leads to the use of the later opinions. (See End of Shabbat below.)