I dont know how your managing this, but remember, all the apps (google+, voice, books etc) show their own usage. currently my Android OS is at 1.78Mb after a few day... If i knew how to post a pic from work i would but i cant. I like to have all my Google services running. And aside from maybe...battery my phone is not affected. My Google Music is however at 181Mb, therefore i pinned my favorite album.