I've got several characters planned for my novel who will each, individually (but with some overlap) interact with the central premise of the story and be affected by it in some way. I want to set up context for each character to set the scene and to give then a reason to be affected by the technology about which the story is written. My question is, how long should I spend setting the scene and developing the reader's understanding of the characters before I get to the main point? The central premise is a technological advance, so I am considering having the characters witness advertising for this technology and reflect on it in their inner monologue, thus giving the reader a glimpse of what is to come. But I'm still concerned that too much time spent setting the scene will cause readers to give up before they get to the main point. I am intending to approach an agent with this book and I'm also concerned that they won't be able to read far enough in to discover the main thrust of the plot if I spend too much time early on setting the scene. However, I'm concerned that if I don't spend enough time setting the scene then the reader won't identify with the characters or understand their motives.