I recently bought a lumia 925 and am struggling to reduce my data consumption. i tried to inactivate background data but to my disappointment apps on my live tiles such as Whatsapp i couldnt access them!! Setting the monthly data limit doesnt really reduce background data usage, but just helps to track usages. i dont download videos or audio files on my phone just web pages. with my old nokia e72, i would really not notice the data usage.