Milan for a few hours?

Hopefully this is up to date ...

Information baggage deposit at the Milan Central Station
(Deposito Bagagli a mano della stazione Milano Centrale)

Milan railway station baggage deposit at the same second floor of the tracks of train. You can deposit suitcases, bags, backpacks, and trunks to one account. Be careful to not lose the stub of your deposit ticket.

Location: In front of platforms 5 & 6 on the second floor
Opening Hours: 06:00-24:00

Price (per baggage):
First 5 hours: € 3.80
6 to 12 hours: € 0.60 (per hour)
After 13 hours: € 0.20 (per hour)

Rules:
Weight limit of 20 kg for one single item.
No responsibility for damaged luggage.
Hazardous substances, hazardous materials are prohibited from deposit.
Luggage check can not exceed five days.

This TripAdvisor thread may be helpful, but I suggest Googling "luggage storage Milan" and clicking on several other links in addition, to be sure there's no important newer information out there.

I haven't checked luggage in Milan but have done so in other cities in Italy and elsewhere. Never a problem, though there can be a line of several (or more) people when you return to pick up your bag, so you really must not cut it too close if you're trying to take a specific train onward from Milan. Also, that TripAdvisor thread mentions security checks of the bags as you leave them, and that will take time as well.

I have a small lock on my suitcase to make it a less-attractive target on the off-chance I run into the rare dishonest employee, though I've never heard about a theft from a checked bag. Locking the bag seems a simple and reasonable precaution; it's something I do when I leave my hotel room, too. When I check a bag, it doesn't include any electronic gear except perhaps rechargers, because my phone and tablet are in my cross-body purse on travel days.

I assume you know that the Last Supper tickets need to be arranged way in advance. I think I've heard of people getting up in the middle of the night to snag tickets the instant they go on sale. If you somehow miss out on that and it's really important to you, check right away for tours that include Last Supper access. I'm guessing that there are less and more expensive tours and that the cheaper ones sell out at some point.

Even my 70-year-old mother with a severely compromised respiratory system was glad she had climbed up to the roof of the Duomo. It's pretty much a must for any visitor to Milan.

Fantastic! Thank you both for these great replies! I love the help of fellow travelers who have gone before.

A few hours can be eaten up fast. I doubt you will have time for a tour to get to see Leonardo's Last Supper, I sometimes use a ticket broker instead (perhaps 100% markup on face value of the ticket). You need about an hour to get in and out. Then go to the Duomo, look around, go to the roof (at least another hour, perhaps two), take the metro from the piazza directly to Milano Centrale and pick up your bags.

My only trip to Milan was four hour stop between Florence and Tirano. Three hours was about right to store and later retrieve our luggage, tour and climb the duomo, and have lunch. More would have been really rushed. There was no line at the luggage storage, but it still took about 20 minutes to a half hour each coming and going.

Just an fyi.....to access .restrrooms at milan rail station you go down a flight of stairs walk.about a block, and then must have a one euro coin to drop in the turnsttyle (like a subway gate) to enter. I say this just so you know that is also a potential time suck.....some one could be qued up to retreive bags while someone else makes the trek to the restrooms. (or wait & use facilities on the train) If you are pressed for time, another of yr family members can purchase sandwiches and bottles of soda rt there in train station. That is about the only location i remember encountering aggressive pan handlers(young woman blocking stairs, reaching for my bag saying "I carry bag for you"........step back chick, i carry my own bag ). Other than those tips we have already given you, station is clean enough & user friendly.

I wonder which train you are planning to take? The current timetable has intercity services that stop at Monterosso, departing at 12:10, 14:05, 16:05.