It’s the day after a blizzard, which mean it's time for Chicagoans to once again trot out their favorite arguments for or against Dibs, that famously divisive practice of using chairs, sawhorses, and whatever other detritus you found in your basement to reserve a parking spot, spoils for having shoveled it out.

The same questions come up each winter. How much snow must fall before Dibs may be invoked? For how long may one stake claim to a Dibbed spot? And, Am I a bad person?

Having the wrong answers to any of these questions can lead to violence and ugliness. Fortunately we now live in an era of data and analytics. To avoid conflict, simply use the following calculator to guide your Dibs etiquette. Heed its recommendation and you'll never, ever risk being a bad neighbor again.