There is no such thing as too long or too short when it comes to a mane because this look is free flowing and cannot be accurately defined. However if you wish to maintain the elegance of this look you will definitely opt for a length that at least reaches your shoulders as the shortest length to be defined as a mane and the length that touches the mid region of your back as the longest. You can surely opt for a longer mane but that will not only be difficult to manage and style but also not a very good look! Somewhere around the mid back, this style stops being rugged and dirty so that’s where you apply the breaks!
This being said, fashion is free from rules. This look when short should be split up into multiple layers especially for men with wavy hair to ensure that your hair has a personality of its own! As it gets longer you may want to start roaming around with a rubber band and also use some hair spray to keep it in check if you are paranoid! As your hair gets longer it is more difficult to maintain and that is why the maximum length suggested here is the ideal length!