Remember the overstuffed wallet, bulging with cash, cards, and who knows what else? If you’re like me, you had at least one uncle who carried one of them, always in a back pocket, usually to the right side because he was right-handed—and that back pocket was permanently distorted into the shape of the wallet, even when the pants had come straight from the laundry.

I don’t see those much anymore. I suspect three trends are at play:

First is the move away from cash. I’ve averaged almost 149,000 air miles per year each of the last two years, and I honestly can’t remember the last time I needed cash for anything except tips at hotels and restaurants: door attendants, auto valets, coat attendants, and of course housekeeping.

Next is the move towards tap-to-pay. This hit home for me when I was at a research conference in Switzerland in 2019. The conference was in a small mountain village, Les Diablerets, and much to my surprise, Apple Pay worked—not here or there, but everywhere. Then I had a day off and visited Glacier 3000, a nearby mountaintop tourist attraction accessible via cable car. While I was at the top, I bought a small souvenir, held out and rotated my wrist to pay with my Apple Watch without thinking about it, and when it worked, the clerk and I looked at each other. I think we both said “Wow.” Almost anywhere you go in the developed world, you can tap-to-pay now, and while that includes credit cards, Apple and Google’s wallet technologies replace them.

In the US, the last holdouts seem to be those restaurants that still take one’s credit card to a register to swipe it, but they’re gradually giving in. Europe and Asia are far more civilized, bringing the terminal to one’s table. And gasoline stations—tap-to-pay is spreading there, but they tend to upgrade their technology slowly.

Finally is the casualization of menswear. When a suit jacket was part of everyday male dress—look at home movies from Disneyland in the 1950s to see men in two-piece suits—a wallet could disappear into an inside breast pocket. Today, even men who care a great deal about clothing may spend most of their time in clothes without those roomy pockets: knitwear, polos, or the like. That pushes the wallet into their trousers, where every extra millimeter matters.

So if you’re not wearing a jacket with roomy breast pockets, you don’t often need to carry cash, you need credit cards only occasionally, and as a man, you—well, to be honest, you don’t want to look like one of my uncles back in the day—what do you do? I can think of two options:

You can carry a bag and keep your wallet there. This has been my strategy for the last few years. I have a leather messenger bag and a nylon daypack that I use for just those purposes, with the choice depending on context.

Or you can strip your wallet to the essentials. What does that mean? Your mileage may vary, but here’s how I think about the essentials of a wallet:

The way I think about the above is that I have the equivalent of seven credit cards (my Nomad locator card is a bit thicker than three credit cards) + as many business cards as I think I might need for the day. That doesn’t take up much space—or at least it doesn’t have to with the right design.

Driver’s licenses and credit and debit cards are generally 0.76 mm. That makes 3.04 mm for the four cards. The Nomad Tracking Card Pro is 2.5 mm, which brings that stack to 5.54 mm (0.22", less than 1/4"). If we treat the business cards as a separate stack, 5.54 mm is enough for about 15 business cards on typical cardstock.

In other words, if stored efficiently, a driver’s license, three credit and/or debit cards, a locator card, and 15 business cards need only take a total of 10.94 mm (0.43", less than 1/2"). If a wallet is designed efficiently enough, it can hold 11 mm of cards and be barely noticeable in a front pants pocket. Put simply:

A wallet should be able to hold half an inch of cards without turning it into an inch or more—or one centimeter without turning it into two.

Yesterday’s wallet—with its six or more card slots, its multiple cash and receipt slots, and the ability to expand to a thickness that was unwieldy at best—solved a problem that, for many of us, no longer exists. We carry little or no cash, use our phones and watches to pay for most things, and can fit the physical cards we still use into a stack less than half an inch thick. That should change what we want from a wallet. In today’s world of luxury wallets, capacity isn’t the goal; efficient use of space is. In other words, the question isn’t “How much can this wallet hold?” The question should be:

How little wallet do I need to hold what I actually carry?

In next week’s Field Note, I’ll look at what happens when you take that question seriously—and why the simplest wallet design I found turned out to be the one I chose.

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