I chalked up about £12k in CC debit between the ages of 19 and 22. Lots of it was spent on, well, gooseberry fool. Still paying a chunk of it back to this day as I had consolidated it and then re-spent back on the cards before I wised up
Ironically, I now have far more CC's than I ever had before, but this time (thanks to working in a bank and learning some financial lessons), they're either all 0% or there's the MBNA CC that is 7.9% for the life of the card for any and all transaction types. Keeping that safe for emergencies. And most of them are clear, just a couple with 0% balance transfers on them, chipping away at them each month.