In general, the purpose of offering free samples in a retail store is to encourage customers to try the product, realize they like it, and buy it right then and there. Trader Joe’s has a sampling area in the back of the store for this exact purpose. But when I tried to get a small sample of the featured coffee, the dispenser struggled and wheezed, with barely any coffee to speak for it. The container was basically empty, and I had to ask a staff member for a fresh one.

It’s a little strange that they’d let the samples run out, when the whole point of having them is to provide an effortless way to try the product. When the dispenser or tray is empty, some people will ask for assistance. But the majority of people will probably just give up and move on, with no chance to try and buy the featured product.

If you want to get the greatest sales lift from your product sampling initiatives, make sure the products don’t run out. The exact technique isn’t important: maybe you’ll choose to accomplish this with extra-watchful employees or with a technical solution, such as a coffee dispenser that shows the fill level on the back. Either way, keeping your samples well-stocked maximizes the chance that people who are curious about the product will actually be able to try and buy it.