Your own mug is a simple way to cut kitchen waste. It does need space, rules, and a device that can handle it.
For people to use their own mugs, three things are needed: somewhere to keep them, easy washing, and a coffee device that the mug fits under. Without these, most people will still grab a disposable cup.
Mug storage
A shelf or rack close to the coffee device. Labeled spots prevent mix-ups.
Fit with the device
Check the clearance under the spout. Many devices, including coffee vending machines (publisher's site), can skip dispensing a cup so you can use your own – ask the supplier whether your model allows it.
Reminders without lecturing
A short note by the device and a few spare mugs for people who forgot theirs are enough.
FAQ
Should the company buy mugs for everyone? It is a nice idea, but not essential. A stock of company mugs works too.
What about travel mugs? Check whether they fit under the device's spout.