Where is the Duomo?

In Piazza del Duomo, right in the center of Milan.
Is it necessary to book in advance?

Yes. Demand is extremely high throughout the year.
What is the difference between Combo Lift and Culture Pass?

Combo Lift includes elevator to the terraces + museum. Culture Pass includes archaeological area + Scurolo + museum.
Can I take photos inside?

Yes, without flash.
How long does the visit take?

1–2 hours for the interior; 2–3 hours if you add terraces, museum, and archaeological area.
Is it accessible for people with reduced mobility?

Much of the complex is accessible; some historical areas have limitations.