Interesting, I usually book the whole trip because I'm looking for the shortest/fastest route and don't want to get stuck at the transfer station during a long break in the trains. But I have to admit the phone app has been a real game changer in terms of being able to plan and buy on the fly.
The absolute best was before they implemented the black out around the departure time. If you could physically get on the train you could buy a ticket for it as/after you got on. Now even if you get to the station and the train is 10 minutes late and you can physically get on it you can't buy a ticket via the app.
And outside Rome, Naples and especially Bologna changes aren't usually all that bad. I always try and warn people about Bologna because it is so different. I have a change in Bologna and I'm currently planning on spending an extra twenty minutes and doing regionale to regionale instead of regionale to fast trains to avoid the pressure of the transfer down 3 levels there.
But as someone who remembers the giant phone book like trains schedules before websites even it is so much easier and more straightforward now even with the strikes, delays and other factors.
Happy train travels,
=Tod