I had a bad experience last year when I was in US. After a couple of weeks of continuous travel, I ran out of my credit limit. I had to call my bank every time I used my visa card. The credit card company even called my employer because I was travelling on business. Later on, I called my bank to increase my credit limit to 22000 and applied another credit card. Now I have two cards and over 40000 credit limit, so I don't need care about it any more.