How often does the metro come?
'Quanto' — KWAN-to. The 'qu' is always followed by 'a' here — a common Italian pattern.
Ask this on the platform when there is no display showing the next train time. Very useful early in the morning, late at night, or during disruptions when service is reduced.
'Ogni quanto' means how often or every how long — literally every how much. It is a very common colloquial expression: 'Ogni quanto vai in palestra?' (How often do you go to the gym?). 'Passare' is used for transport passing by a stop.
Ogni quanti minuti passa il treno?
Every how many minutes does the train come?
More explicit version asking for the interval in minutes.
Quanto aspetto?
How long do I wait?
Focuses on the waiting time rather than the interval.
C'è un orario affisso?
Is there a timetable posted?
Asks whether a schedule is displayed.
Rome's metro runs every 5–7 minutes during peak hours and every 10 minutes off-peak. Milan's metro is more frequent — every 3–4 minutes at rush hour on busy lines. Both systems have real-time departure displays on most platforms.