Gwalk900 is correct. Here is why. Many of us have several devices. Sometimes I have 3 computers on at the same time and an ipad in sleep mode. Sometimes only 1. Sometimes only 2 are on at the same time. You get my point.
If you have a device misbehaving and downloading even a few megabytes, with an hourly history you can quickly determine which device(s) is the problem.
Fortunately my router allows me to track usage is several ways.
Usage per day per device:
Traffic Statistics overall including hours of activity:
Traffic Statistics by an individual device including hours of activity:
For me it serves as a counterpoint and perhaps as a "proof" to what Hughes claims I used. While the Hughes previous data hourly display was "overall usage" it still was a valuable tool to have to be able to define a period of occurrence.
Mine is an Asus RT-AC3100 running the asuswrt-merlin firmware that enhances the stock Asus firmware;
The 3100 can be a bit pricey for some budgets but here is a list of other Asus models that also run the merlin firmware:
(click on picture for larger image)
At times you can find factory refurbs with full warrenty through places like Newegg amoung others.
I got a little off track last month, but this month is going much better.