I'm fixing the networking at my mom's house right now, and it's an utter hack job. Every room is set up with an Ethernet jack, along with cable and telephone. The person who installed the jacks and picked the equipment for the network cabinet wired at least 2 of the jacks incorrectly, and didn't label ANYTHING. Confounding the matter, both Directv and Comcast technicians have had their grubby little fingers in it too, and there is now a mix of random, unlabeled coax from both networks. There are 2 signal amplifiers, along with a few splitters.
To top it all off, the initial guy cheaped out and used a 8 port 100mbit switch. There are 12 jacks in the house. The modem and router are in a random upstairs bedroom right now. I can't put them in the network closet yet because I need to sort out which of these random wall warts powering all the cable stuff can be removed safely. I'm probably going to need to redo a lot of the terminations on the ethernet, and a few on the coax. There's an 8 port splitter just sitting on the floor too, it looks like someone just cut the ends off the cables and left the connectors there.
My mom is going to be out a few hundred bucks by the end of it. We need a new switch, and she already had to buy a new modem and router to replace the on that Comcast provided. The Comcast one did not support more than 1 wireless client without crapping out, and they wanted $7 a month for the POS.