How many times do we take the same route to the same places. You know where you need to be and you know 1, maybe 2 ways to get there. So you take those. All the time! I know I do it and it's not until someone points out a much faster way that I even realize there is another way to go.
In my new story, my heroine moves from San Francisco to LA and uses her GPS constantly. She knows exactly 1 way to get to work and 1 way to get to her lover's house. Poor girl claims she uses her GPS so she can learn to get around but no--she relies on it too much to learn the routes.
I do have high hopes for her, though--she's a cop after all, and has to learn the city eventually!