train reservations?

hello again

one last time with the train questions:

i am going to buy point to point in italy
but as i am looking at trenitalia.com, i notice that some of the transfer trains between the places i am going, have an option to choose "mandatory reservation" or just "seats".

if i buy a ticket to go from florence to la spezia and there is a transfer in between that has the mandatory reservation option, does this mean i will have to make a reservation?
and if i am buying point to point at the stations, how far ahead of time do reservations need to be made?

if none of that made any sense, i guess, to put it simply:
if i am doing all of my travelling during the day, in what situations would i need to make reservations? and can they be made at the train station as you are leaving?

EuroStar Italia trains require reservations. For InterCity trains, like the ones in your Firenze-La Spezia example, you have a choice between "mandatory reservations" and "seats only." This means that a reservation is recommended but not required. "Mandatory" isn't literally true. Your fare will be 3€ lower if you don't reserve.

Whether a train requires a reservation or reserving is recommended, you can get that reservation up until shortly before departure--if seats are available.

On regional trains, reservations are not even possible.

Edited by: timothysolberg

thank you.
i finally understand