The practice of pausing on fixed moon-days for religious observance was not unique to the early Buddhist community: Jainism keeps a closely related observance called posadha, using a cognate term and a comparable pattern of periodic lay and monastic intensification of discipline on fixed lunar days, and both traditions most likely drew on a shared older North Indian custom of treating the phases of the moon as natural points for religious pause, rather than either tradition inventing the practice independently of the other.
How strictly uposatha is kept today varies considerably across the Buddhist world: in Thailand, Myanmar, Sri Lanka and other Theravada countries the day remains a well marked point in ordinary religious and even civic life, with some countries restricting alcohol sales on the day and many lay Buddhists visiting temples specifically to take the Eight Precepts, while in East Asian Mahayana countries and among many Buddhist communities in the West the fixed lunar rhythm has faded from everyday practice for most laypeople, surviving mainly within monasteries themselves, where the Patimokkha recitation continues on schedule regardless of how many, or how few, lay visitors take part in the day from outside.