DD is going to be a senior in college and lives off campus in an apartment. She has a checking account, savings account, a credit card, and an ATM card (linked to both checking and savings accounts). Actually, it's DH's credit card, but she is the second person on the account so the card has her name on it (and it's a Disney VISA so she gets points!). She uses the checking account to pay her rent, phone, and internet, and uses the credit card for almost everything else. She knows she is responsible for covering her COL bills from her checking account, and we pay for her food, medical expenses, pharmacy charges, etc., that come through on the credit card. If she needs clothes she discusses purchases before using the credit card for them- she is still a student so we cover her basic needs. If she wants clothes, she uses her checkbook or cash, if she thinks she can afford it. (The difference between need and want!). She uses her ATM card (fee free, regardless of where it's used) to deposit her paychecks and take out some pocket money ($20 a week, maybe), but never as a debit card, so she can't over-draw anything. She is pretty frugal, so this works well for her.
Actually, DD is very trustworthy with the credit card and will call before she uses it for anything, even a trip to Dunkin Donuts, and rarely dips into her checking account, never her savings account (she wants a car
sigh
). She's pretty responsible.