Years ago, I mean back when I was a baby agent, I sat on a conference panel with about three other agents. During the panel the question of exclusives came up. Since this has always been a (odd) passion of mine I spoke up to say how wrong I felt exclusives were. Another agent disagreed.
She spoke up and said that she always asked for an exclusive. Her reasoning was that it was a waste of time not to because if a “bigger” agent offered, writers were going to go with the bigger agent and she wasted her time. First, I was shocked that she didn’t believe in herself enough to think authors would benefit from being with her and second, I was shocked that she actually justified locking authors in without any options.
So we argued. And it wasn’t pretty, but I bet it was fun for the conference attendees.
Agents still ask for exclusives and authors still need to respond to that. My advice on saying no to an exclusive is you kind of don’t.
When an agent asks for an exclusive I would still send the material and simply say in my letter, “I’m afraid I can’t offer an exclusive since I have queries/requested material out elsewhere. However, I will gladly keep you informed should another agent come forward with an offer.”
Simple and straightforward and my guess is that the agent will read your material anyway.