It usually takes me 45 minutes of standing in line at a major railway station in London to buy a railway ticket. Having allotted that much time to do so today, how long did it take in total? About five minutes.
The flip side of "saving" time: I was intending to go to Cambridge sometime soon to visit a friend, but a sudden family death has sent her back across the Atlantic and there is no longer time to see her. It technically saves me a trip to Cambridge, but one I had rather wanted to make; and that makes it seem much less like saving time at all.