Understand how agents earn: by taking a % of your earnings. (Usually 10-15% and possibly 20% for eg film/TV/foreign rights, because they often pay a sub-agent). So, if you realise that the average advance for a children's book is £1500, you'll see why many agents don't take children's authors, for example. You are also unlikely to find an agent if you a) are a poet b) only have one or two ideas in you c) don't appear to have a commitment to a long career or d) are really annoying. (Because really annoying authors tend to earn less. With the exception of Mr ... But no, I don't know you well enough to say more.) Non-fiction can be hard to get an agent for - unless, again, it's likely to be very commercial. Essentially, you have to have the ability to earn dosh. And ideally have a perfect personality. And never phone on Sundays.
But back to whether you want an agent. Well, put it this way, I'm not about to get rid of mine, despite the fact that I've had many books published happily with several publishers. Why do I hang on to her? For many reasons:
- I want to spend my time writing.
- She can mediate between me and the publishers if I'm pissed off with them - so they can think I'm sweetness and light and she can be the bad cop. Not that I ever am pissed off with them, of course ....
- She knows what all the other publishers are looking for and can tell me when she thinks I'd be interested.
- If I want to write something different or approach a new publisher, she's best placed to handle that and to know who to go to.
- She understands all the boring bits of my contracts and knows what everyone else's contracts say and what things publishers can be budged on.
- She regularly meets all the publishers and also other agents.
- She will fight for me to get the best deal.
- She has foreign sub-agents and TV/film agents and has regular meetings with them.
- She goes to the trade fairs and tells people about my work.
- I can run a new idea past her and she can tell me if it's rubbish, before I've embarrassed myself.
- She is an honest and expert second opinion when I've written something, and can tell me what to change before I give it to my editor. So my editor thinks I'm brilliant.
- She can nag my editor. So my editor thinks I'm calm.
- She accompanies me to all publisher meetings. And plays bad cop. So everyone thinks I'm lovely.
- She knows everything about the market, and tells me. So people think I'm clever.
So, you work it out for yourself. If you want to do all that, then do it.
BUT. You need to know what you can expect from an agent. Not all agents do the same, so when you're looking for one, you must ask what that agent can and won't do. Some agents do PR as well, but this is not usual, so do not expect it. Just ask exactly what services you can and can't expect. I would also say do make sure your agent is full-time and professional, not just doing it as a part-time hobby.
Openness and honesty are very important. It becomes much much more than a business relationship and it can be tricky to tread the line between professional respect and friendship. I think I've been very lucky but I know many other authors who feel the same way (and some who don't). The main thing to remember is that your agent wants you to have the most successful career possible - because your success is her/his success. And income.
There are some authors who choose to have no agent and who manage very well. They are exceptional - either exceptionally clever and strong or exceptionally foolish.