The traditional normal period of engagement is two weeks.
You need at least 3 weeks for the banns to be read.
Yes, that’s true. The banns were a regularization of local custom and the origin of the current “engagement period”. This shows that the church considered the time between “three consecutive holy days” as a normal waiting period.
This is an interesting article highlighting the changes and differences in marriage customs throughout history.
https://scholarsarchive.jwu.edu/cgi/viewcontent.cgi?article=1037&context=student_scholarship“ The Elizabethan Era continued many values and practices from the Middle Ages. Some similarities in the wedding planning and celebration included a formal public announcement of the marriage, a feast following the ceremony and religious affiliation (more similar to the end of the Middle Ages than the beginning)...
The public announcement that the couple was to be married was called “Crying the Banns” and this “announcement would be made in church, three Sundays in a row. This is different than the announcements of the Middle Ages because in this time period weddings began to be much more religiously-affiliated.” (Knight, 2008)... This was a similar but slightly more formal announcement than that of the Middle Ages...
Although this era did not bring many big changes to wedding ceremonies, it did introduce some key aspects, such as the decoration and the announcement formality that we see today in many weddings. Decoration is a huge part of wedding ceremonies in modern times, and the Elizabethan Era brought about the beginning of that custom even though at this point in time, the decorations served a dual purpose to cover up lack of hygiene. This also marked the beginning of a more significant notice of engagement and even a longer period of engagement prior to the wedding as a result.“
Just like today, the expensive decorations are what cause the delay.
The Amish still have short engagements.
It’s interesting reading “Wedding Customs and Folklore” that even this was considered an imposition and the popular option for the rich was to pay for a marriage license, which dispensed with the need to wait for the banns.
“In New York too, banns were only for the vulgar, special licenses genteel, until retrenchments provoked by the Stamp Act forced a change of mind. A newspaper report of 13 December 1765 referred to the aversion thus:
‘We are creditably informed that there was a married last Sunday evening... a very respectable couple that had published three different times in Trinity Church. A laudable example and worthy to be followed. If this decent and for many reasons proper method of publication was once generally to take place, we should have no more clandestine marriage; and save the expense of licenses, no inconsiderable sum...!”