Best time to apply for upgrade to normal Amex card

[bm_999]

Hi all, just wondering is there any best times to upgrade the amex that we have?

Not sure if gold or platinum is best or even maybe 1 of the barclaycards etc..

Thanks

[NorthernLass]

Which card do you hold and which are you considering upgrading to. Barclaycard is not Amex, of course.