How to increase credit limit on American Express credit card?

I've held this card for 3 years. Quick reality check: the welcome benefit is good, the first-year fee waiver is easy, but from year 2 onwards you really have to work for the milestone benefits. Don't keep it if your monthly spend drops below the milestone threshold.

On the add-on card: yes, the primary cardholder is fully liable for all spends on the add-on. There is no separate credit limit or statement. So only issue it to someone you trust absolutely — spouse, parents. Not friends, not siblings you have money disputes with.

Forex markup comparison: Amex = 3.5%, HDFC Infinia/Diners Black = 2.0%, Axis Atlas = 3.5% but with milestone fee waivers, ICICI Emeralde = 3.5%, Standard Chartered = 3.5%. If you travel more than twice a year, the math favours Infinia or Diners Black.