Do You Allow Spiders to Survive?

I am sitting here doing homework and see a cellar spider casually walking along the wall. He sees me notice him and freezes for a minute before going along his way. I notice that he is on his way to the top corner of my room where I spot a smaller red spider chilling up there. Perhaps that's his buddy. Maybe he wants to eat him. I'm not sure.

Obviously, a person with common sense will kill a brown recluse or a black widow at first sight. F*** those guys. But do you ever just let a spider go? Do you and the spider have a truce where you let him live in exchange for killing other insects? Or is it one of those "stay out of my sight and you live" types of deals?

:o