Is your BACKSTORY too long?

Every characters starts with an idea. That idea then turns into a story. That story is what drives your character in game to do stuff! So you gotta come up with a backstory in order to get your adventurers "Why"! But how long should that be?---------------Music provided by Kevin MacLeod (incompetech.com)Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0Music also provided by Monument Studios