https://www.bart.gov/news/articles/2009/news20090309

You know what, I used to plan my leaving from home based on the timings at the station, but soon I realized that it is not worth it. It is not because trains are not sticking to the time table. Just randomly starting at your own comfort eliminates the anxiety that comes with planning. Your average wait time might increase to half of the interval between the trains, but that would be an increase of only a few minutes for mornings, in return for never bothering to check time again.