Many commuters in London also leave when they want to leave, or close to it. Metro trains run every 2-10 minutes on most of the network (I'm including the ends of the lines there), urban/suburban/regional trains around every 10-20 minutes.
Personally, if the service is at least every 10 minutes I won't check the time when I leave. If it's 20 or more I will, and in-between probably depends on the weather and if the station is indoors or not.
Personally, if the service is at least every 10 minutes I won't check the time when I leave. If it's 20 or more I will, and in-between probably depends on the weather and if the station is indoors or not.