When I personally write a character I think of what I want to happen to them and how it may/can/will be changed due to the actions in roleplay or otherwise. Some characters or NPCs are destined to go from good to evil or the other way around. Some characters have pre-planned plot points in their story that I either decide when I want in or ask the GM about such as my Naruto Character Mitsuhide Senju. I won't go into detail in order to prevent possible spoilers for roleplays I have with him. 

On the other hand I build characters like Harry Lancer or Galen Dracos whom both exist to just evolve as the story goes on. I'm not sure if that this is what is considered in what Prince is talking above but it's how I roll with things. My motto for the former character is this, "Destiny is predetermined but events can change it slightly." due to the one trigger that is going to turn the character into what he is supposed to be late term games. My motto for the latter is, "Just go with the flow." While they have their own strict personalities Galen and Harry would have simply adapted and gone with the roleplay as it happened they have no predetermined destination.