Does It Have To Be That Hard?

I recently saw an online discussion about the process of building your character. It was suggested by one writer that a stagnate storyline, or lost motivation, implies you've not learned your character well enough. Likewise, a non-fiction book about writing mentions doing a full write up on your characters; that to really understand who you're writing about, you have to get in their head, know every facet of their personality, history, future.

Does it really have to be that hard?

I've never been one for structured outlines, so it goes without saying that I don't lay my characters out on paper before I begin my WIP. Oh, I sort of do it in my head, create their appearance and general state of being. But I "see" my characters so clearly, sometimes (okay, most often) because they're based on people in my life, that their personalities, their mannerisms, how they behave in certain situations, play out in my mind's eye. I don't have to refer to notes or files to understand them.

My goal with this post isn't to say "Look at me, I have it easy" or to knock other writers' habits. I'm just wondering why the perception is that a character has to be so thoroughly sketched out before one can begin. Yes, I get that if your course isn't planned out you may well get lost. But is it a crucial technique for virtually every writer? We all know each writer is different, with varying habits and methods. Our techniques may at times overlap, but who's to say we have to follow the same unwritten rules?

What about you? What's your method for building characters?

And do you think writers make things harder for themselves?