Why do you care about resource usage? Well, most of the time, on a modern system, you don't care because everything works fine automatically. However, when a newly installed device does not work correctly, or when an old device stops working after a new one is installed, one of the first things to suspect is a problem with the resource assignments.

Windows uses a process called Plug and Play to assign resources to your hardware as needed. It works pretty well most of the time, but you might occasionally run into situations where two devices both stubbornly claim the same resource and have a conflict. In cases like that, both devices usually don't function correctly.
Conflicts are pretty rare on modern systems, but back in the days of Windows 95 and 98 they happened a lot.

On the Resources tab in the figure below, look at the Conflicting device list text area at the bottom. It says No Conflicts. If there were a conflict, information about it would appear here.

One way to resolve a conflict is to clear the Use Automatic Settings checkbox on the Resources tab for one of the devices, and then manually change the resource allocation for it. However, on systems that use ACPI (that is, most modern systems), that checkbox is unavailable for most devices. For example, it's unavailable in the above figure, which means that Windows is not willing to let you tinker with the resource assignments.

Another way to resolve the conflict is to remove one of the conflicting devices from Device Manager (select it and press Delete), and then let Windows redetect it. When it redetects the device, it looks at the available pool of resources and picks resources to assign to it. Windows doesn't usually recreate a conflict; instead, it assigns different resources.
An exception might be if both devices are hard-wired to insist on certain resources. This can be the case with very old devices that were created either before Plug and Play was invented or during the transition period when devices could work either with or without it.

If there are jumpers on the device that set its IRQ or memory address, and those jumpers are set to a certain specific value (rather than being set for Plug and Play), the device just won't work unless it gets the resources it wants.
In a case like that, you can try to change the jumper settings on one or both devices so that they no longer conflict.

Plug and Play requires three things: a Plug-and-Play compatible operating system (such as Windows 95 or higher), a Plug-and-Play piece of hardware, and a Plug-and-Play motherboard in the computer. Fortunately, all computers sold within the last seven years or so meet all these criteria.