Premium cards are easy to justify on a spreadsheet. The harder question is whether the credits fit the life you already live.

Start with cash you would have spent anyway. A benefit that sends you to a store you never visit is not worth face value; it is an invitation to spend. Lounge access is similar. It has real value when it changes a trip, but not every visit is worth the price of admission.

The useful calculation is personal: annual fee, minus natural credits, minus the value of benefits you consistently use. Everything else is marketing.