Once I saw on an episode of *This Old House* that they were putting in hot water return lines: pipes that recirculate idle hot water back to the heater so you get hot water right away, instead of wasting time and water.

My wife and I are looking to getting our first home and I think this might be a beneficial investment to make at some point. I also am skeptical of the cost.

Is it worth it to install them? Or is it a matter of convenience?