"The internet is bad" is nine different problems

• "Pages crawl on every device"
• "Video drops to a blurry picture"
• "Downloads take all night"

Speed is how much data fits through each second. It is set by the narrowest point on the way in: your plan, your provider, the line into your home, or the router that shares it out.

The common mistake: Buying a faster plan first. If the line or the router is the narrow point, a bigger plan changes nothing.

• "Fine in the lounge, hopeless in the bedroom"
• "One laptop is slow while the phone beside it is fine"

The internet is reaching the house at full speed. Wi-Fi signal fades with distance and walls, and a weak signal forces the link down to a slow rate. Or the device itself has old Wi-Fi hardware.

The common mistake: Blaming the NBN or changing provider. The fault is inside the house, so nothing outside it can help.

• "Good in the morning, poor from dinner until bedtime"
• "Streaming buffers at 8 pm and is fine at 8 am"

Every household in your area leans on the network at the same time. If your provider has not bought enough capacity for that peak, everyone on it slows down together. On wireless and satellite connections the tower or satellite itself is shared.

The common mistake: Upgrading the router. Your equipment is fine; a different provider on the very same line can be faster.

• "Everything stops for a minute, then comes back"
• "Video calls freeze and reconnect"
• "Games kick you back to the menu"

A dropout means one link in the chain broke and had to reconnect. Which one is the whole question: the line in the street, the NBN box, the router, or just the Wi-Fi. The lights on the boxes tell you, if you look while it is happening.

The common mistake: Restarting everything and never looking at the lights. The restart hides the evidence of which box lost its connection.

• "Speed tests look fine but games rubber-band"
• "People talk over each other on calls"
• "A pause before every page starts to load"

Delay is how long one message takes to get there and back. It has nothing to do with how much data fits through. A connection can be fast and laggy at once. The usual causes are Wi-Fi retrying in the background, a router that makes small urgent messages queue behind big uploads, or a connection type with distance built in.

The common mistake: Paying for more speed. A wider pipe does not make each message arrive sooner.

• "Nothing loads on anything"
• "Wi-Fi is connected but says "no internet""

Somewhere the chain is completely broken: an outage in your area, a box without power, a box that has lost its connection, or a cable in the wrong socket. Working from the outside in finds it quickly.

The common mistake: Factory-resetting the router straight away. If the fault is an outage you gain nothing and lose your settings.

• "No signal in the garage, the backyard or upstairs"
• "It works by the door and dies two steps further"

One router can only cover so much. Brick, concrete, metal roofs and distance all stop it. The fix is to carry the network closer to where it is needed, and the right way to do that depends on what you will use there.

The common mistake: Buying the cheapest extender for everything. It is fine for a doorbell and a poor choice for gaming or work calls.

• "Port forwarding does not work"
• "The console says strict or moderate NAT"
• "Cameras cannot be viewed away from home"

Going out to the internet works, so everything looks normal. But nothing outside can start a connection in to your home. Either two routers are in a row, or your provider has you sharing one public address with other customers.

The common mistake: Endlessly re-entering port forwarding rules. If the address is shared, no rule on your router can work.

• "The doorbell goes "offline" every few days"
• "A new plug or bulb will not join the Wi-Fi at all"

Smart devices have small, weak aerials, usually speak only the older 2.4 GHz kind of Wi-Fi, and often sit outside or at the edge of coverage. Modern router features can also lock them out.

The common mistake: Returning the device as faulty. It is nearly always the signal or a router setting.