How early to book trains?
I'll be arriving in FRA on 10Aug 10:30am. I intend to immediately travel to stuttgart.
Later on, I plan to travel to Paris on 11 Aug and then London 13 Aug. I don't mind booking these two in advance, however I would prefer some flexibility on the the FRA-Suttgart trip since I can't predict if my flight will be delayed.
How far in advance should I book these trains?