You can let it search for a connection all day and it will still be the lowest power consumption your phone uses. No point in ever turning it off.
I was gonna then whats the point of using wifi at all if it eats battery while not talking to an access point. It should just go basically idle/sleep mode like some NIC cards
I agree with the original post. I used to monkey around with my wifi turning it on/off whenever I thoguht I should, but now I leave it on and haven't noticed any difference in power consumption. The same goes for my GPS radio. And to your point, I believe (and I'm sure someone will correct me), that the combined use of the wifi and gps radios to learn your locations governs when and where your wifi turns on and off. For instance. If I am not at home or office, I do not manually turn off my wifi radio, yet it shows as off anyway. I assume since it knows I am not near any known wifi connections, based on the gps location and availalble wifi networks in range.