How do you decide which grants to apply for and which ones not to?

I've always been very lucky in that at each of my jobs I've had the lattitude to make those decisions. I've been able to make those decisions - relatively on my own - because I maintain excellent communications with program and other staff so that I always know organizational needs and wants. As I'm doing research or as opportunities arise, I'm generally able to take advantage of them because I'm always abreast of what's going on funding-wise and organizationally.