I can give you a few answers to that. But I didn't mean it as a general dilemma regarding every aspect of your life. I meant it as a general dilemma regarding characters. So... when getting to know a character, how much is too much for you?
I personally love characters - they're my favorite part in a book, and I love to know loads of things about them: their habits, their preferences, how they grew up. When writing a book series, a lot of this stuff sorta comes with the territory. But when does the writer go overboard?
In Hunters, seeing as it was a one-volume thing, I didn't dwell a lot on my MCs background. Some people wanted to know who Rachel was before she was turned - I gave a few clues, but I honestly didn't bother thinking up her entire life since before she turned 24. In the new version which is now up for review, I cleverly inserted that she used to be a med-student before becoming a full-time vampire hunter.
I have no such backstory for Daniel, though his story is a lot more interesting than Rachel's. People strangely never asked me about what he got on with before he stopped aging. I do have his backstory in my head, but it's too long and too complicated to squeeze in the original story. I do give some hints, pointers and it's gradually revealed that he suffered from memory loss.
I'm just wondering how many actually wondered what Daniel was doing before he started hunting vampires. Just so you know, he was a cop :-p
In my series, I get a lot more of my characters across, though there's a lot of them. Tom and Jimmy's past never comes into full focus though there are pointers of how they struggled to make a living and some ouchy relationships. But, other than that, it's full speed ahead.
Kyle's childhood is even more draped in darkness, at least until volumes 4, 5 and 7. The 7 part is important to the plot, but the info I give in 4 and 5 are more likely get-to-know-the-character than anything else - how he grew up, how he met Kay and so on. Short stuff anyway. I wonder if anyone will care...
Which leads me back to the initial question: How much info can you give about a character without it becoming annoying? I don't think there's a right or a wrong here - you can't give ALL the info in your book for plot purposes, or characters wouldn't be well-rounded. I mean, what importance does favorite food, color or type of music have? BUT, do those things help you identify with the character better? Do you like them more if they have the same tastes as you, the reader?
I have my character's entire life in my head - I know their nightmares, their dreams, their favorite outfit, the fact that they don't like peanut butter, their signs and birthdays... who cares except for me? Because if it helps in the least make a connection, I'm dripping that s#!t in. ;)
How much is too much?