I think you should only use credit cards if you can completely pay off the balance at the end of each month. That's what I've done so far. I've probably charged around $30,000 to one of my credit cards over the past couple of years, but I've paid the balance in full at the end of the month.
Also, make sure you don't lose the bill and forget to pay it. That happened to me one time and I had to pay interest plus a stupid late fee.