Eine Reise eintragen am besten so spaet wie moeglich-kann jederzeit, soll an sich jedoch vor Antritt/Zugbesteigung geschehen sein. Can enter travel details best as late as possible, also does NOT yet have to be when making REServations (when needed). We have seen so many problems here from enthusiast people who did it weeks ahead and then had to change plans.

Thanks @mcadv genau das, hatte ich nicht verstanden, da überall steht, man soll eine Reise planen und im Trip speichern. Aber ist der Trip aktiviert, kann ich wohl nichts mehr ändern. 
thanks @mcadv that is the point I didn’t understand. I always read: plan a complete trip, add it to pass and travel. So you mean create a trip with the first journey and then add a new journey at the day I travel again. Is that right? 
yours Gerd 

You always have one trip connected to a pass; you choose a name when you activate the pass. In that trip, you can store journeys. Before boarding a train, you still have to add the applicable journey to My Pass. After that, a QR code is generated to show the ticket inspector.

You can always remove journeys from My Pass, for the whole journey or train by train. You can also remove journeys from your trip.

I normally don't use the app to plan, since its timetables don't get enough updates to be reliable. National planners are more reliable, or the DB planner for most international planning. I just add a journey to My trip shortly before travelling (or maybe the evening before) and just before boarding a train, I add it to My Pass.

Hello @rvdborgt thanks for your explanation. So best is to create a trip with the first journey for this trip and connect it with my pass.  Then adding every day a journey to actual trip at my pass and create again ticket! And do on! 
best wishes Gerd