I had a limit of 6L and got dcb in December. Spent about 13-14L in 5-6 months, then realised I'm screwed and stopped spending. Then emailed hdfc after 3-4 months of 0 spending to upgrade card to infinia to which they agreed. But I wanted fee waiver at 5L spends for which I went to the BM and convinced him and he got me 5L waiver for infinia with a limit of 6L.
PS: Still a student