Testers

Cable testing is important because it pinpoints any incorrectly terminated cable.  Most home users don't buy testers and that is ok.  If you are doing a large installation or are multiple installations, it may be useful to test the cables.  Simple testers test only for cable continuity, while more complicated testers can certify the performance of the cable. 

Another way of testing the cables is to simply plug a working network device, like a computer, into a jack and see if the LED on the hub comes on.  If it does you have data flowing through.