Does turning off data (mobile+wifi) when not actually using any app help at all (on Android)? Will apps still be able to phone home in the background? Or will t

Does turning off data (mobile+wifi) when not actually using any app help at all (on Android)? Will apps still be able to phone home in the background? Or will they just fill up a huge cache with data and bulk-transfer it the next time the phone is online? Maybe at least disconnecting from the internet while not using it will make location tracking slightly more difficult?