24 hour metro card(yes I will be using multiple times)--half the websites say it expires in 24 hours, half say it expires at midnight of day of purchase. Does anyone have definitive answer? With the 24 hour card, you stamp/validate upon first use and then not again until your last trip. At the metro, you validate entering the station AND exiting the station. So how do I exit(or enter) station if I've already validated ticket perhaps from an earlier bus ride?
What city?
If, as your other post indicates Rome, 24 hours from first validation. See my answer to your identical question on the other thread.
I think tam is asking about either Milan or Rome.
The italian versions of ATM (Milan) and ATAC (Rome) sites, the official ones, clearly say that now passes expire in 24/48/etc hours. Maybe there are some English pages not yet updated? Otherwise tam could be looking at some non updated, amateur website like Ron-in-Rome.
Metro turnstiles "understand" when a ticket has already been stamped and if it's still valid. They won't stamp it again, don't worry.
If it's Rome, here's all the info you need on passes:
http://www.atac.roma.it/page.asp?p=229
(click "English" on the dropdown under "italiano", upper right of the page)
Click on each option for longer descriptions. Yes, the 24-hour pass expires 24 hours after first validation and not at midnight. You only have to worry about validating a pass ONCE: the first time. At the metro, you'll insert it into a slot in the entry turnstile and collect it again when it spits it out a slot at the top.; it'll time/date stamp it. If you have to exit the station through a turnstile, repeat the process. You'll do this each time you use the metro during the life of the pass, and it doesn't matter how many times you've used it during your 24 hours.
For buses, validate the first time in a machine near the front of the bus, where you should board. If already validated, just flash it when you get on.
For commuter trains, validate at one of the small machines near the tracks.
Inspectors on any mode of transport who may ask to check it will note the date/time of first validation.
Do be aware that the pass will not cover you for trips to or from the airports.