I certainly am no expert on this subject (perhaps a musicologist can add their thoughts below?), but it is my general understanding that notation was much less specific in the 19th century (and earlier) than it has been in the 20th and 21st centuries, undoubtedly for practical reasons. Since so much music was written in the tonal system and since so many people were trained to understand and interpret tonal harmonies in a relatively consistent fashion, it wasn't as necessary to indicate a decrescendo at the end of a phrase or a crescendo into a section where the harmonic rhythm would begin to accelerate.
Today we have composers writing in an infinite variety of styles and idioms, some of which have implicit interpretive traditions and others of which do not. I have encountered composers (teachers and peers) who deal with this potential interpretive black hole by erring on the side of notating every parameter of each musical gesture. Being the diligent student that I usually am, I typically follow suit. But recently I performed a piano piece of mine in a masterclass run by a composer and a pianist and the pianist suggested to me that my notation was almost too specific...that a lot of the implicit aims of my gestures could be understood by the performer, without having my explanations cluttering the page. So how should we, as composers, handle notation?
