Train Tickets
Buongiorno,
The earlier you buy your tickets the less they will cost (warning: the more you go back and look at the site, the more they increase in price.) Sometimes in the summer you will find 2 for 1 specials, but there are a few restrictions on those types of tickets.
If you know your dates, and they are (hardly likely) to change - then I would get your tickets early. However, if you are a "fly by the seat of your pants" kind of person - and never really know your schedule, you can wait. It is highly unlikely that you won't find space, you will just find that the prices are a bit higher by a couple of Euros.
I just recently went to Milan from Florence and I checked out both Trenitalia and Italo trains. I went with Italo because of the times - but they were really neck to neck with their offer. The train ride was about 2 hours and cost around 25Euros one way.
Buon Viaggio,
Donna Denise