How early should you reserve trains?

Having never been to Italy myself, I'm not the best source of factual information. However I have been asking that question all over the place and from what what I understand it really is no big deal to get your tickets at the station. We are going with this option for many reasons but mostly because we don't want to have to commit to a time to catch a train. My sister is actually going to get a saver pass however my husband and I, based soley on our research decided to "wing-it" and use the automated ticket machines when we get there. But, others may disagree and our route is not the same as yours.
Hope this helps.

Jon,
Depends on if you are traveling 1st or 2nd class. Also time of year, if you want a sleeping car, and near holidays. I myself will be traveling in April and we are traveling on one leg which is six hours so we decided 1st class would be more comfortable for this long of a trip. We reserved our seats and purchased our tickets last week online and already recieved our tickets. I have family in Italy and they tell me usually there isn't a problem buying your tickets a few days before you travel unless you are on a tight schedule and you have to be at a certain place at a particular time. This happens to be our situation so we decided to buy and reserve now so we don't have to worry about this. The only negative is you have to pay a small fee to do this, I paid a 15.00 fee for 4 tickets.

Greg

The overnight trains can be very popular on these long-haul runs, especially on Friday nights....personally, if I NEED to make these trains, I would book in advance. Register first at http://www.trenitalia.com/en/index.html then book ASAP after you have received your e-mailed password. You will also be able to take advantage of Amica fares over the web, which can save you 20%.

I just finished booking all my train trips in Italy via Trentitalia. They open bookings up 60 days in advance. The site has some flukes, especially with US charge cards, passwords. Doing it again, I'd book all my legs at once in one "shopping cart". We booked as each leg opened up because we have a large group and wanted to be sure we sat together. There are "agencies" who will book for you, or if you're flexible you can book once you're in Italy. But I hate standing in lines and wasting time almost as much as paying fees for something I can do myself. You print your tickets and board the train. Have fun!