There's an annoying NBN commercial which pretends to be giving helpful advice about installing your wifi router, which includes the advice to put the access point in central location close to where it will be used the most.
Nothing wrong with the advice, except that, short of rewiring, you need to put your router within a patch cable's length of the NBN box, which in turn is plugged into what was originally your master phone socket.
Fine if your master socket is in the middle of the house. Ours isn't, it's at the front of the house, because that's where the phone socket went when it was originally installed. The patch box on the outside still has a Telecom Australia logo on it, it's that old.
Now, our house is an 1890's weatherboard cottage with a modern extension on the back.
Originally there was an extension socket in the extension but that was plastered and tiled over when we remodelled the kitchen and built a sitting and TV area on the back of the extension.
This all happened before we had the NBN, and had a Telstra ADSL connection. The old Telstra ADSL router happened to produce a pretty powerful wifi signal so everything worked, even though the unit was at the 'wrong' end of the house.
We did have a bit of ethernet run down from the study at the front of the house to the sitting area, and we connected the internet TV decoder to the wired ethernet. The wireless signal was a bit attenuated so I bought one of these $10 no name wireless repeaters from ebay to allow us to surf the web while watching TV.
When we changed to the NBN and changed ISP's that meant a new router, but everything basically kept on working the way it had.