Where I can, I typically wait for the next service to begin, however if it isn’t for a while I’ll just go back to the menu and select a new one, the longest I’ve waited is around 30 minutes on an ECW service. There are a couple of things that DTG missed with SEHS - stock moves to Faversham sidings to change ends, and clearer journey details within the main menu timetable, both of which would of been decent QoL additions. Personally I’m much more likely to wait in game for a service if I can do so aboard the same unit, I’m less likely to wait over 10 minutes on a platform for a new train to arrive.
I'm probably in the minority here and like to play it in "Real Time" so I'll choose a service at the same time it is now and complete that then go to free roam. Best is to do a run from St Pancreas down to Faversham then a few local runs back and forth and then run the last 395 back to London.
How can I tell if a services is terminating at Faversham? Up to this point I've only done the first 395 services as route learners, so I didn't bother too much about that.