During these three months, monks cannot spend the night outside the area they have taken for rains residence. If they have to go out, they make sure to return before dawn of the following day. There are, of course, exceptions to this rule by which a monk is allowed to spend the night elsewhere - for instance, if his parents are seriously ill, or if he is required for some urgent religious work at a place too far away to return in one day. But even in such cases, he may be away only for seven days at a stretch. This practice, like many others, has been preserved to the letter down to the present day, and the period is considered by all Buddhists as exceptionally sacred to perform merits.