Currency

No. Take your ATM card. Use a bank operated ATM once you are in Switzerland. It works just like at home. You will get Swiss Francs at the best possible rate.

Most US credit cards are accepted everywhere. You might have difficulty at unmanned kiosks when the credit card machine requires a PIN.

Make sure to inform your bank when and where you will be in Europe so they don't cut you off. Some banks no longer require that, but check to be sure.

You will need Euros in Milan and Franks in Switzerland.
Changing cash at a bank is the most expensive way to do it, you have to pay for the cash to be transported, and for the bank employees.
The cheapest way is to use your normal ATM card in an ATM at your destination. Euros from an ATM in Milan.

Some people like to have a little bit of cash so they are not panicking to find an ATM when they land. In which case get ~€100-€150 (not Franks), enough to fund transport from Milan airport to the hotel and a first meal.
Then get some Franks from a Swiss ATM after you cross the border.

Most places take credit cards, but always check, some don't. For small purchases (under ~€20 / CHF 50) cash is preferred. You may find cards are only accepted above a certain amount (typically €10 or €20)

Make sure you have told your bank you will be using your cards in Italy and Switzerland, otherwise they might block them as a suspicious transaction.

You could buy Swiss francs from your home bank. But you'll get a better exchange rate if you use your bank card at a Swiss ATM when you get there. As long as your card has a Visa or Mastercard logo on it or is part of the Cirrus or Plus systems. Ask your bank if overseas use is allowed.

Credit cards are widely used except in the smallest of stores or markets, but you'll still want cash for smaller purchases.

And don't forget that you'll need Euros in Milan - not francs. Oh, and notify your bank and credit card companies about your travel plans before leaving home, so they don't freeze your account when there's an atypical charge.

ETA: looks like we were all replying at the same time.

Read the “Money” section in Travel Tips on this website. It’s recommended that the easiest and most economical way to get foreign currency is to use ATM’s while overseas. For the most part Visa and MasterCard are almost universally accepted in Italy and Switzerland. American Express is not accepted as widely but is in many larger hotels and restaurants.

Determine if the bank that you use for your ATM withdrawals and the issuer of your credit cards do not charge extra fees or foreign exchange fees. It’s easy to open a bank account and get credit cards that are traveler friendly. The two most recommended in this forum are Capital One and Charles Schwab.

Some travelers advise getting a minimal amount of the currency of the country in which you start your trip. I have not done that and never had a problem. When using ATM’s make sure they are bank owned not privately owned to get best rates. If you are asked if you want your transaction in $US vs. local currency, called dynamic conversion, NEVER do it. You’ll always get a bad fx rate.

On our trip to Switzerland last week, and previous visits, we found that everyplace we went to takes credit cards. While we used an ATM to get 50 francs, we ended up using for a purchase because we didn’t have a credit card on us at that moment. Previous visits, we withdraw 20 francs, just in case. Since Switzerland seems to be more than double the cost of where we live in Italy, charging 2 coffees for 10CHF seems reasonable, but we would never charge the same two coffees here for €2,20.

We also found that 90% of charges defaulted to USD, so make sure to change to CHF option before clicking on OK button.

We also found that 90% of charges defaulted to USD

Thank you for that tip. We've been going to France regularly, and have almost never had that issue there, but we'll be spending a few days in Switzerland in April, so now I know to look out for that. I had gotten lazy about it. The one time I missed it was at the Dublin airport, where I wasn't paying attention. Fortunately it was just a couple of beers.

Last July I noticed in Barcelona and in Switzerland that almost every time a credit card machine wanted to use US dollars and I had to manually switch it to the local currency. I didn’t find hardly anywhere in Switzerland that didn’t take credit cards with the one exception of the Chinese restaurant in Mürren which only took cash, but they took francs, euros, or US dollars.