Here in Sweden debit card is far more common than credit card. Expences for the company (hotel, taxi, travel) ans so on is commonly payed with credit card.
One reson is there is no such thing as a FICO-score here. If I apply for a credit card the company will take a "credit control" that will state my income last three years, and weather I at any time last years did not pay debt or bills on time (number of times). The later, even if just once = big trouble.
If I sign up for a cell phone plan the operator want to se an income, but $7.500 yearly probably will do the trick.
There is no point in keeping credit open for a long period of time or acting strategically in any other way than: 1) pay bills and debt 2) make more money in order to raise "credit score". Two people making $ 100.000 a year (no credit bloopers past 5 years) can borrow $425.000 mortage on a house if they put in 15% down payment. Housing market here is still kind of crazy...