I am fortunate to receive many invitations to visit book groups, schools, book fairs and the like. When I turn down the majority of invites I get (or simply fail to see the invitation in my disaster of an inbox, on twitter, facebook, etc) I sometimes get the response, "You seem ungrateful," or, "Don't you want to sell books?"
I've realized that most people don't understand the ins and outs of being a writer for a living, so I'm going to talk really frankly here. Many are offended when writers talk about money. Art and commerce shouldn't mix! Authors are artists and shouldn't make decisions based on dirty filthy lucre! For those people I say, Look away! Don't read this! Go on believing that artists survive on art alone and need no home but the earth to whom we compose odes and eat nothing but delicious, nutritious words and are sated.
For the rest of you, let's talk some practical numbers.
Often people assume authors are like widget makers. You see people at Costco doing demonstrations of blenders. They'll sell more blenders if they're there in person. An author sells more books if they're there in person too. But authors make much less per item than a blender maker. And traditionally published children's authors make the least of all.
Case study. A children's author and an adult SF author go to a book signing. They spend two hours there and sell the same number of books.
The adult SF author has a 700-page tome that sells in hardcover for $35. Writers get higher percentages for adult books, usually at least 15%, so each hc sold earns the author about $5. Sell 50 and he's got $250. Paperback prices vary (mass market much less than trade) but let's say it's about $15 for a paperback. He makes about 10% on that, sells 50, earns $75. For two hours plus travel, that's decent. He'll also get to meet many fans, which is another bonus of doing events.
Now the children's book author. The hardcover sells for $18. Children's writers make about 10% on a hardcover, so if she sells 50 that's $90. For a paperback, $8 with a 7% royalty is common. For 50 books that'd be $28.
Adult author total: $325.
Children's author total: $118
Plus agents take 15% off the top, and then authors are self-employed and so pay higher taxes.
Now these are big numbers. Selling 50 hardcovers and 50 paperbacks at a signing is a great signing for most authors, so this is just an example. I've done signings where I've sold zero. All authors have. And even though a 100 book signing is tremendous, I have to sells tens of thousands of books to make a living at it, so even having a few great signings several times/month wouldn't enable me to write for my job.
There are vast variations on this. If it's an illustrated book, author/illustrator spit the royalty, so a picture book author who didn't do the illustrations might make 5% on a hardcover and 3.5% on a paperback. Board books are even less. Scholastic bookfair books might earn an author 5 cents each, or less.
Given that children's authors make so much less on books than adult authors, they usually charge to make appearances, do school assemblies, etc. Many can afford to be a writer because of extra income they make from appearances. When you ask a children' author to come to your event for free, it's like asking any other professional to work for free. I can't count how many times I've been invited to speak at a function for free even though the attendees paid to be there. Children's authors (and especially women) are often expected to give of our time for the cause and be grateful for the opportunity. And actually, I am always grateful that anyone thought of me, but I simply can't afford to give away so much of my time.
A self-published author would have an entirely different experience at that book signing. Let's say she has a novel she sells for $15 and half of that is the cost of the book, so she makes $7.5 per book. That's a great number. Signings are much more worth her time. The downside is that her books are less likely to be in bookstores, so in order to sell books she needs to be present. This is one reason why ebooks are usually a better option financially for indie authors.
Usually when I do a signing, the majority of books I sign are ones the readers bring from home, which is perfectly fine. If I sign 200 books at an event, perhaps 40 of those were purchased that day because of my appearance. I do around 50 book events/year, and for most of them I make less on the royalties from books sold than I pay my sitter to watch my kids while I'm gone. And while I'm gone, I'm also not writing, not creating that next book.
For reasons of publicity, all exposure is good exposure. But as a writer who needs lots of time to produce the next book and as a parent who doesn't want to raise neglected kids, I have to be very selective about where I put my time.
This year I started to do school assemblies one day a month in my home state. Halfway through the year I'm beginning to think I can't afford to do it again next year, even though I'm getting paid for my presentation. I get about 18 work days/month, after you take out weekends, holidays, and the inevitable child-related interruptions. To give up 1/18 of my work time is significant. I'm not sure I can afford to do it anymore. Even though I love to meet the kids and it feels great to be there, and it is great publicity to personally meet all those kids who may want to read my books in the future, ultimately I'm a writer and I can't afford to lose my writing time.
So, that's the nitty gritty. It's not fun, is it? Much more fun to talk about story crafting and character development and writing sentences that sing. Money and art may not be a happy couple, but until art can be created by robots, artists will always have to think about it. And note that even though authors don't make much per book, they make even less if you pirate them. Please, please don't be a book thief. Read The Book Thief but don't be one.
Even though there is a lot of stress that comes with this unpredictable, unstable profession, I love it so much and am so grateful for those who read my books, who buy them from bookstores or check them out of libraries. I wish I could meet you all in person. But I promise that I'm not that interesting. My wild, fearless hope is that the stories themselves are enough.
Please feel free to ask me any followup questions in the comments.