Well, I play Pokemon Go and it has Adventure Sync, which credits walking-distance towards the hatching of eggs and getting candies from your buddy when the application is not open. You just keep your phone in your pocket as you walk around.
Since Monday 9 am, I have so far walked 45 kilometres. I will definitely go over the 50 mark when it'll be reset tomorrow at 9 am. Note that it's the first time I'll hit that mark since the feature became part of the game a few weeks ago, so 45-50 km are my weekly average walking distance.
So, roughly I walk 6-7 km per day. But it's winter now and I don't go outside for long. Summertime, maybe 10 km per day? I'll see eventually in five months.