Routers, Switches and other network devices contain quite constant data, which are changed very rarely. Mostly there is configuration, what is changed. However every configuration change can cause unexpected issue. The most problematic is human factor or firmware issue. At last there is a posibility of hardware failure. For all these cases is handy to have any configuration backup, better the latest.
Each of network device vendors has own system to get the device configuration out. But almost none has automatic configuration backup system. This place tries to get project called ConfiBack.