[legion]

Another thought:

Let's say a purely hypothetical municipality has a budget of $10. The only two projects proposed are fixing the pothole on the town's one street and paying the local artist to paint a mural on the side of the town hall. Both cost $10. If they fix the pothole now, they can pay the artist to do the mural next year. If they pay for the mural now, it will cost $12 next year to fix the pothole as it will have gotten bigger.