I've said for years that reuse has to be as easy as single-use. Ideally it should be invisible. If using the reusable option is slower or more awkward than taking a paper cup, most people will take the paper cup, and no amount of signage will change that.

Which brings me to the question I'm asked most often: what's the best technology for reusable cups? It depends entirely on where it's being used. A system that's ideal in a café can be unworkable in a stadium.

A reusable cup system has to do three things. Charge the customer, get the cup back, and keep it circulating. The way you do each of those changes completely with the size and rhythm of the operation.

At re-universe we support three models: Two-Tap, Integrated and Invisible. We don't start with the technology. We start with the operation and work backwards.

Three venues, three different problems

Picture an independent café, a visitor attraction and a football stadium.

A six-month trial we ran at a university café displaced 55,000 single-use cups, in the region of 300 drinks a day. Blenheim Palace gets through around 500,000 cups a year, roughly 1,400 a day, with a steady flow from opening to closing and a lunchtime rush. A stadium we've been analysing hires about 50,000 cups for a single major event, and serves most of them in two short windows: the build-up to kick-off, and half-time.

A system that works beautifully in the café will produce a queue down the concourse at the stadium.

There's a second problem that nobody likes discussing. Most reuse providers built one piece of technology, and that technology is what they recommend. If a company's expertise is QR codes, you'll be offered QR codes. If it's a separate card reader at the counter, you'll be offered a two-tap setup. I understand why. It doesn't mean it's right for your venue.

Two-Tap: the easiest way in, and the most hands-on to run

The biggest obstacle to reuse is rarely the cup. It's the till.

Most venues already have a payment system that works, and they're understandably reluctant to replace it or pay for integration work. Two-Tap sidesteps that. The customer pays for the drink the usual way, then uses a separate device to register the cup and take a deposit or a hold on their card. The two systems never need to talk to each other.

That makes it a sensible starting point for independent cafés, multi-site schemes where every venue uses a different till, and pilots. It can be live quickly and cheaply.

The cost is in the running of it. There are two payment interactions instead of one. Say that adds four seconds. At 300 drinks a day, that's twenty minutes spread across the whole day and nobody notices. At 50,000 drinks in a match day, it's more than 55 hours of extra time at the tills. Spread across a hundred service points, that's half an hour added to each one, and nearly all of it lands in the rush before kick-off and at half-time.

Returns are the bigger limitation. With a basic Two-Tap setup, cups come back to a member of staff, who scans each one. That's fine for a few hundred cups. It gets hard as volumes grow, and it means customers can only return a cup when somebody is free to take it.

None of that makes Two-Tap a bad option. Its advantage is that it lets a venue start, without replacing what it already has.

Integrated: one payment, and machines that take the cups back

An Integrated system puts the deposit into the normal purchase. The customer pays once, takes their drink and gets on with their day.

Returns usually go through reverse vending machines. The customer drops the cup in, taps their card and gets their deposit back. The machine identifies and validates the cup, so no member of staff has to handle it.

Refund speed matters more than people expect. I waited five days to get £20 of deposits back after an event this summer. I'd done exactly what the scheme asked of me, and I still felt short-changed. With re-universe the refund is triggered within seconds of the cup being validated, though how quickly it lands depends on the customer's bank.

The trade-off is infrastructure. Integration takes technical work, and machines need space, power, connectivity and maintenance. Each one can only process so many cups an hour.

That suits places where returns trickle in steadily: visitor attractions, campuses, office buildings. It suits a stadium at full time much less well. Even a good network of machines will bottleneck when 20,000 people leave at once.

Invisible: reuse that nobody has to think about

At high volume, the aim is for reuse to be close to invisible. This is where that principle stops being a slogan and starts being an engineering requirement.

The cup is handled as part of the normal purchase, with no extra payment step. When the customer is finished, they drop it into a return point. No code to scan, no card to tap, no machine to queue for.

RFID does the work. The cup is identified automatically at the return point, matched to the original transaction, and the refund or card release follows. From the customer's side: buy a drink, enjoy it, drop the cup off.

It also means cups can be processed in bulk rather than one at a time, and tracked through collection, washing, storage and redistribution. If you want the detail of that, I wrote about what actually happens to a cup after you return it.

The difficulty is getting the infrastructure right: deeper payment integration, well-designed return points, readers, antennas, connectivity, and reliable identification when a hundred cups arrive at once. That's more planning, more testing and more upfront cost. Overkill for a café. For a stadium or arena, it's often the only approach that doesn't make the customer experience worse.

Five questions worth asking before you choose

1. How many drinks, and how fast? Seconds at the till are irrelevant in a café and decisive in a stadium.

2. What till system do you have? One estate with one POS provider is straightforward. Thirty independents with thirty different systems is not.

3. Where will cups come back, and who handles them? Staff, machines or bulk return points.

4. Who washes them, and where? The payment is one part of a scheme. If the logistics don't work, the technology won't save it.

5. Do the economics work? Hardware, integration, transaction fees, maintenance, staffing and losses, all together. The most automated option isn't automatically the most affordable one.

These aren't three rungs of a ladder. Some venues will run Two-Tap happily for years. Others need Invisible from the first day.

There is no single right answer

Two-Tap makes reuse accessible, but more of the work lands on staff. Integrated gives a cleaner checkout and automated returns, but needs infrastructure. Invisible is the smoothest for customers at scale, and the most involved to build. None of them is right or wrong in isolation.

That's why we built re-universe to support all three, so we can recommend what suits the venue instead of what suits our technology. You can see how the three compare on our reuse solutions page.

The test comes back to where I started. Is it as easy as single-use? Would I use it myself, with a drink in one hand, a phone in the other and people waiting behind me? If the answer is no, it doesn't matter how clever the technology is.