Why Wi-Fi routers should be left switched on

There seems to be much misguided advice to switch off Wi-Fi routers when not in use---here is a counterargument.

Leave it on so criminals know less about your habits

Thieves and other criminals often look for clues that might tell them the householder's habits---when they're likely to be out, at home, in bed, etc. Lighting can be one giveaway, but timers etc add confusion. But if you switch off your Wi-Fi when out or sleeping, you are literally broadcasting an "in/out" radio signal to anyone in the neighbourhood who knows how to scan for Wi-Fi networks from their mobile phone. If your Wi-Fi is on all the time then it's not saying whether or not you're there.

The risks of leaving it on are small by comparison

The fire risk, although being non-zero, is probably less than the risk of broadcasting "in/out" information to criminals, and you can take precautions to reduce the risk of a router fire spreading (such as not siting it near carpet or fabric). If you ever consider crime prevention by running lights on a timer, despite the very small fire risk of that, then logically you should also consider crime prevention by leaving Wi-Fi turned on.
The EMF is negligible---last time I checked, it was something like "sitting in a Wi-Fi hotspot for a year is equivalent to a 20-minute call on a mobile phone" so if you use mobiles at all then you shouldn't even consider what you're getting from Wi-Fi because it's nowhere near your biggest source (but if you avoid mobiles then you might also wish to avoid Wi-Fi and just have wired connections, so the rule of "if you have Wi-Fi, leave it switched on" should still apply either way).
If your router is vulnerable to being "cracked" (popularly known as "hacked in") by security attacks, then you have bigger problems---switching it off for some of the time will not very much reduce your risk, because the bad guys are quite capable of coming back and trying again later. It's better to make sure you don't have a vulnerable router in the first place, instead of relying on "they can't break in if they only happen to try when it's switched off" as your protection---especially if this is weighed against the risk of aiding physical burglary.

Leaving it on has speed advantages

Many broadband routers use their idle time to test out which combinations of line frequency bands give the best speed on your particular line today. If you don't let the router have that idle time, you could miss out on the improvements to your connection speed it could have found. And if you have any technically-inclined neighbours who want to account for the exact positioning and channels of neighbours' routers when setting up their own, they will more likely be able to avoid mutual slowdown if yours is on when they're gathering their information.

Power consumption

This is the one contrary factor---a router left switched on can be a "phantom load" of anything up to 25 watts, although the best ones take far less than that. But if you spend any energy at all on confusing burglars, then keeping a low-wattage router on for the same reason seems similarly justifiable.

All material © Silas S. Brown unless otherwise stated.
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