1. Replacing your router (or firmware) almost always fixes your problem.
2. Adding an additional router almost always makes things worse.
Solution: Switch off nodes when they stop working.
My house has this problem. I live on the 4th floor, next to the main VDSL router. The kitchen & living room on the 2nd floor can't get a strong WiFi signal. After some thought about WiFi repeaters, I decided to buy a long Ethernet wire and run it down the stairs. I trip over it sometimes, but it's basically reliable. The downstairs router runs dd-wrt, and works fine 99% of the time (I've had to reboot it once in the past year).
The upstairs VDSL router is owned by the telecom company (Chunghwa), and they don't give me administrator access. I can't change the firmware, and the box is frankly awful. About 6 months ago we complained repeatedly, asking them to replace the box. They sent tech guys, who tested the wire, and said that everything is fine. Indeed, it works about 70% of the time. But very often I come home from work, and I have to reboot that router before I can get online.
My solution is to buy a Edimax WiFi power socket and a Raspberry Pi, which checks to see if it's online. When the network goes down for more than a minute, it'll automatically tell the WiFi power socket to turn the router off and on again.
I know that power-cycling is bad for the router, but I don't see any other solution given the software constraints. I'm also surprised that there are no companies making devices for the purpose of power-cycling routers.
I've not tried one and at around $75 they aren't cheap. I was looking into them at a time when my cable modem would forget how to route anything and need to be power cycled, but replacing it did the trick.
Thank you so much for finding existing products! I'm certainly going to buy one of these.
ResetPlug is for WiFi, but hasn't posted anything since 2016 (I'm a bit worried that it might not exist any more).
Megatec ezPower is in Taiwan (local for me), but is only Ethernet. Often the Ethernet still works even when the WiFi doesn't, so I'll try to get the ResetPlug first.
My parents just used one of those old school mechanical socket timers and had it shut down for 5 minutes every morning at 4 AM. Might not work for you if you have long-running connections you need to maintain...
2. Adding an additional router almost always makes things worse.
While I wouldn't add another router, I've found that adding additional AP's almost always makes things better, assuming they are not on overlapping channels.
I've had that happen, the trick is to place them on the other side of large metal objects (like in rooms behind fridges) or with as many walls between them as possible. It really does come down to placement and how many Wi-Fi hotspots your neighbours run. It's theoretically possible that your 3 Wi-Fi hotspots could run at channels 1, 6 and 11, and try to pin devices to each channel, while still working in one room. But if you've limited Wi-Fi spectrum available, adding more APs isn't going to help things unless they're carefully tuned to transmit with less power/interference.
Except when for some reason roaming don't work for that certain device during full moon. Or after power outage it will boot but not properly and router will work and AP won't. Or AP kinda works, WiFi part at least but there is no internet there for whatever reason. In my case it is a clear case of multiplying problems.
If you have a strong enough signal that adding a new AP is not neccessary, then you don't need to roam. If you have multiple AP's and can't roam between them, you're no worse off than if you had one.
If you have malfunctioning hardware, then you're going to have problems whether you have one AP or multiple AP's -- use better hardware.
How warm is it at your place? I've been quite successful avoiding router lock ups by adding some active cooling: take an old PC fan, solder it to the power wires of an old USB cable, connect that cable to the router (assuming your router has an active USB port).
Taiwan: so hot right now. 32ºC in the day, 26ºC at night.
I've often speculated that the temperature is causing problems, which would also explain why it's hard to reproduce the issue when a telecom service tech comes over. I'll have a look around for a suitable fan, and see if that helps.
I did this on one of my APs that fails frequently (locks up and the front lights go off, signal strength randomly goes down to about 8 feet with no obstructions, etc) and it helped immensely. unfortunately, it didn't /solve/ the problem for me, just made it better. I've ordered some unifi stuff on recommendation from friends. hopefully that'll live up to the hype and do the job.
I decided to buy a long Ethernet wire and run it down the stairs. I trip over it sometimes,
Why not use Powerline Ethernet? In most houses, it's typically fast and reliable and requires no extra wires. E.g. the data rate between my desk and router is currently 784 Mbit/s.
Powerline is a crapshoot, at least as much as Wifi. I installed several different models a few years back, for me and some friends/family, and in every case ended up finding another solution as they would just add another layer of unreliability.
Cheap ones suffer from the same problems as cheap routers, randomly hanging and requiring a physical plug / unplug when the room gets hot, or whatever other interferences degrade their performance over time.
Expensive ones are still not 100% reliable, and most of the time will cost more than a well done ethernet installation.
Never had any problems in three different houses. Two different brands (we use AVM Fritz!PowerLine now). I reliably get high bandwidth and low latency. A gave an old set of adapters to my parents in law who live in an older house (from the 1930s) and it works well for them as well.
Of course, as a sibling said, it'll depend a lot on the wiring and/or other connected devices. So I guess it's best to try with a borrowed pair of adapters first.
I've had one brand that did not work at all, but netgear powerline adapters 500mbps or better have been solid for me even in heavily congested outlets.
These are good but if you have any analog audio/video kit nearby (or if you listen to shortwave radio) you'll hear them.
Also, avoid TP-Link adapters as they seem to have some issue coming out of powersave mode that means I have to ping something all day to prevent them from sleeping
Price. $1500 (50 USD) for power-line Ethernet, $300 (10 USD) for a wire. And the lower latent power consumption, and the fact the wire is less likely to be the cause of any problem.
I'm renting the house, and wherever I move next probably won't have this problem.
I suspect the OP lives in a country where house power wiring is a bit shakey.
In the UK I have had very few problems with powerline one failed through over heating and had an issue when we had our solar panels installed as the POS Netgear router didn't implement STP and we had a broadcast storm
This is how it always ends - wired ethernet where you can and rebooting malfunctioning wireless devices (or all of them if unsure). Why can't we have nice things?..
"After some thought about WiFi repeaters, I decided to buy a long Ethernet wire and run it down the stairs."
Would some of those 'homeplug' plugs that use the mains wiring as a closed circuit low frequency radio signal link be tidier? I used a fairly low speed pair to get Internet from modem/router downstairs to desktop PC upstairs without drilling holes and running cable. Worked ok.
2. Adding an additional router almost always makes things worse.
Solution: Switch off nodes when they stop working.
My house has this problem. I live on the 4th floor, next to the main VDSL router. The kitchen & living room on the 2nd floor can't get a strong WiFi signal. After some thought about WiFi repeaters, I decided to buy a long Ethernet wire and run it down the stairs. I trip over it sometimes, but it's basically reliable. The downstairs router runs dd-wrt, and works fine 99% of the time (I've had to reboot it once in the past year).
The upstairs VDSL router is owned by the telecom company (Chunghwa), and they don't give me administrator access. I can't change the firmware, and the box is frankly awful. About 6 months ago we complained repeatedly, asking them to replace the box. They sent tech guys, who tested the wire, and said that everything is fine. Indeed, it works about 70% of the time. But very often I come home from work, and I have to reboot that router before I can get online.
My solution is to buy a Edimax WiFi power socket and a Raspberry Pi, which checks to see if it's online. When the network goes down for more than a minute, it'll automatically tell the WiFi power socket to turn the router off and on again.
I know that power-cycling is bad for the router, but I don't see any other solution given the software constraints. I'm also surprised that there are no companies making devices for the purpose of power-cycling routers.