[quote=@Inkarnate]
 If I were more confident and trusting with everyone and anyone on RPG I would probably void a CS entirely.
[/quote]

This. I largely prefer doing this with a good partner/set of partner (s) over having to fill in a CS. Is it because I'm lazy, or that I hate CS's or I don't want to characterise my OCs? Nooooo!
But rather because I hate being obligated to stick to that character sheet precisely, for the entire duration of the RP. Especially those ones where they demand multi-para personalities. It's all very well and good to summarise a characters thoughts and beliefs but if I have to spell out every single aspect in several paragraphs then I often find myself purple prosing for the sake of length/word count and that is quite...painful, for lack of a better term. I am then also restricted to having that character only act that way because that's what is in the bio/CS....What about character growth [i]during[/i] the RP which then changes the way my character acts and perceives the world through events they have been through with or without their companions? There's less freedom to do that I feel, when you have to keep to what you've put in the CS. 

I prefer to give a brief summary, such as a list of a few traits and maybe a few sentences to a paragraph that summarises how the traits come together to form their personality, and then let them speak for themselves in the IC. A lack of CS or lack of detail in a bio does not always equal a lackluster author or a lack of thought into the character. Sometimes it's just more fun to let things unfold as the RP goes. Where would all the fun be if I revealed to you their entire back story before it came up in the IC? it takes away half the excitement because it takes away the "shock" factor of me revealing something IC that you weren't expecting because you already knew it would happen when I had to reveal it in the CS.