A lot of agents do queries in their spare time such as commuting, watching the evening news, et cetera. Unfortunately for writers, it's the type of activity that can fit into small chunks of time while being distracted by other things. But on the flip side, I send out queries while commuting, watching TV, and in other small chunks of time, because it's the type of activity I can do while I'm distracted by other things.
Best of luck,
Jim Clark-Dawe