It is recommended that in these churches and oratories an annual solemn exposition of the Most Blessed Sacrament be held for an appropriate period of time, even if not continuous, so that the local community more profoundly meditates on and adores the eucharistic mystery. Such an exposition is to be held, however, only if a suitable gathering of the faithful is foreseen and the established norms are observed.
Source: Code of Canon Law (Vatican.va)