[throwanem]

Does it actually help on your phone? I should think that falling back to cellular data would potentially consume more power, since the chipset will increase tx/rx power to compensate for weak signal. Or do you turn that radio off, too?

[Markoff]

yes it helps and i have pretty much always disabled mobile data unless i am expecting something important, so there is no fallback, though always enabled mobile data would be battery wise much more serious issue than WiFi which is pretty efficient nowadays

[exodust]

I keep both WiFi and cellular data off unless I need them. Don't like the idea of my phone churning through background processes and network activity from my pocket.

[Vendan]

Running the wifi radio at all when you know there is no network to connect to is pointless, and does waste some small amount of power.

[amnah]

You turn off wifi when you know that you won't be using it, eg, when you go outside of work/home.

[pbhjpbhj]

Some people will not want their phone connecting to WiFi because they don't want tracking, eg around the supermarket.