Over the years I have frequented many writers' boards without ever commenting, even though I have dearly wanted to. Everywhere, on every site, people are obsessed with getting an agent. I can’t tell you how many times I have wanted to post something to the effect of: "don’t worry about that now, trust me, you are not ready."
The majority of people asking for advice want to know how many queries other writers sent out before they got an agent asking to see their book. And then how many of those were requested before an offer of representation was made. And then how many editors were queried. How many of them responded. How many this, how many that, how long did it take you?
Don’t ask those questions. Seriously. Don’t. First of all, there is no formula. You cannot devise an algorithm that will be true for all writers at all times. That’s like trying to come up with a unified field theory based on Wikipedia articles.
Many writers are concerned about time because they want to know how soon they can quit their crappy day jobs. They see writing a book and selling it as an escape from regular work and it can be if your last name begins with a K or a Rowl and ends with an -ing. For the rest of us…I’m not saying it won’t happen for you but what did I just say about asking questions like that? Seriously. Don’t.
Write knowing that more likely than not, your book will not get you an agent, will not sell, will not take you away from your crappy day job. The odds are vast and they are against us. Write only because you love it.
Why do I feel the need to say this? Because most people who post on those boards truly do not feel that way. They may say they write for pleasure or because “they have to,” but let’s be honest. That ain’t true. When you forgo friendships at work or at home, when you put off having a family or a pet for years and years, when you arise early to write every single day (not only when the muse is visiting), then you can say you “have to write.” But until then, it’s merely an enjoyable, frustrating hobby that allows you to daydream about not working at your crappy day job.
P.S. Even Kafka worked a day job his entire life.