Although I always carry a credit card with me, I tend to use my debit card for ATM withdrawals and most purchases. But, I now have a separate debit card that I use exclusively for travel. It may be unnecessary, but I prefer not to expose my entire debit account when traveling. Therefore, I’ve set up a second debit account with my bank and simply deposit my trip money into it. As
@jeanineonthecamino said above, I withdraw cash generally enough to get me from city to city. The only problem that I’ve found withdrawing money from an ATM is if the bank is a small regional bank. It may not accept your card. However, ATM withdraws work great at the larger banks like Santander. In the past, I found carrying about €200 cash was sufficient. With higher prices now, I’d probably bump that up to €300.