I primarily use AMEX for the frequent flyer program, Mastercard for emergency charges for places that don't take AMEX, and a Visa debit card for cash. Being a debit card, I don't think there is a daily limit with my Visa, but I would be curious to hear information to the contrary.

There are two types of problems I have encountered. One is as you describe--the credit request is made and denied. I have never had this happen with AMEX. I did make one major purchase that they questioned, but they spoke to me directly over the phone at the time and had me answer some questions to establish my identity. However, I have had it happen more than once with Mastercard, though never domestically--once was when I bought a computer locally at a store that did not take AMEX. They did not ask to speak to me; they simply denied it. I had to call them back to get them to accept it. The reason, of course, was that it deviated from my pattern. That is another reason I don't like to use Mastercard personally.

The second situation is when your card is not accepted because of some real or apparent malfunction. While a bit removed from your original question, I note that it tends to happen when someone wants me to use my Mastercard instead of my AMEX (AMEX charges the vendor more, but it doesn't affect the buyer), and it is not a rare event.

Ira H. Bernstein Dallas, TX 75230