When would I use a 24 hour session?

24Hr mode is useful for when you are trying to find a leak around a PRV or something else particularly noisy.

They allow you to see the difference between night and day. In the above example, we can see the large peaks at around 200 and 700Hz that are normal for a PRV. Between 23:00 and 05:00, when the PRV is less strained due to lower usage, we can see that the peak around 250Hz persists.