I stay motivated to keep pushing into bigger volume because I know these campaigns wont last for ever. When they die off, I don't want to have regrets of not working harder on it. I work the hardest when something big is running for that reason. 100% energy into the big winner. You have ultimate focus. You are not fluffing around with little bits and pieces, and don't get distracted with hot new angles.
I also have motivation to beat my high score.