I just became aware of a setting on my iPhone that caused me quite a bit of consternation.
It tracks where you go and if you go to the same place more than a few times it keeps a record on the place as a Significant Location. It even records how you got there and how long you spent.
You can find it and switch it off at Settings > Privacy > Location Services (you need this turned on to find your punts) > right at the bottom of the list is System Services >right at the bottom of the next list is Significant Locations. Before you turn it off you might just look at what it has been recording.
If you want to leave it on you can clear the record by turning it off if you want to.
Depending on your thoughts on privacy you might also go to Settings > Privacy > Advertising (Press and turn on Limit Ad Tracking)
This You Tube link provides more information
Maybe most of you already know about this but it came as quite a shock to me.
Happy punting