I've just seen an interesting blog post on 'which is the most important aspect of a novel?' Personally, I'd say the question is meaningless. Character and dialogue, for instance, can't be separated - you develop a character through what they do and say. Setting? How could setting ever be most important? You could write some dreary old crap, even if you set it an exotic Inca court where everyone ate parrot kebabs with the feathers still on from golden skewers. Setting must either be absolutely integral - the story couldn't take place anywhere else - or it's window dressing. Everything has to happen somewhere. (Doesn't it? Could I write a story set nowhere?)
The blogger's answer is 'character'. The post links to the author's Character Chart, which opens in Word and is so exhaustive I think I'll retire now I've read it. I'm not a great one for planning at the best of times, but I really don't need to know the date of my character's grandmother's birthday in order to write consistently. Really, I don't. And as for preferred home decor style, whether they have ever been fined, and their favourite board game - huh? Am I doing it all wrong? The characters come into my head and I watch them do things. Then I write it down. They are like real people. I can tell what real people are like even if I don't know when their grandmother was born or whether they wear contact lenses.
I have a serious suspicion that answering questionnaires about your characters is a displacement activity - it's easier than actually writing the story. And knowing the answers doesn't help you write the story. It is not knowing your character is an Asian psychopath with a liking for poodles that counts, it's being able to build an an Asian psychopath with a liking for poodles from nothing but words. That's the hard bit.
Seriously, though. Do you do all this stuff? I often have pictures of my characters, and perhaps a page of notes on them - but sometimes not. Sometimes I have nothing except what is in my head. How do you do it?