I would advise you not to add a train from your trip to a travel day until you know it is going as you cannot cancel a planned travel day after midnight the day before. That saves your travel day if you are unable to travel on the cancellation day so there is no need to reinstate it.

If your train is cancelled the operator is obliged to rearrange your journey at no loss to you even if that entails a hotel and an alternative train the following day, which they should supply free of charge so again no travel day is needed for that one, but you may need to show your active ticket for the cancelled train.