The eight precepts are how a layperson tries monasticism on for a day. On uposatha observance days, and throughout a retreat, the usual five are extended: the third changes from avoiding sexual misconduct to celibacy outright, and three more are added — no solid food after midday, no entertainment, cosmetics or jewellery, and no high or luxurious bed. In Theravada countries older laypeople in white robes keep them at the temple on full-moon days as a matter of course. The one everybody talks about is the noon rule, because hunger arrives on schedule and makes an abstract undertaking extremely concrete by about four in the afternoon.