Parish Records exist from around 1560 until the introduction of statutory registration at the beginning of 1855. The exact dates covered vary between parishes, with most having no surviving records at all until the late 18th or early 19th century. For details see that parish's page.
Similarly, the content of the records varies greatly, even within the same set of records, being largely dependant on the person keeping the register.
Because of the violence of the persecution of the Catholics during the Reformation, few records survive. The collection at Blairs College, on the south bank of the Dee near Aberdeen, which is the main post-reformation collection, was transferred to Edinburgh in 1958.