Is the fad of Stanley Tumblers over? It just might be once Gen Z, the generation strongly committed to sustainability, figures out that Stanley Tumblers may not be environmentally friendly after all.

Of course drinking water out of the 40oz container is beneficial to the environment if you are drinking out of it for the rest of your life, but if its just hanging around with a whole collection of them (don't be the woman who stole 65 of them), then you're not helping the environment.

Truth is, the environmental impact of manufacturing a Stanley stainless steel cup is significant, so you really need to use that cup everyday to make it worthwhile. And unlike its competitors, Stanley doesn't yet offer a buyback or recycling program for cups at the end of their lifecycle.

Hydro Flask has a trade-in initiative for its old bottles, ensuring the recycling of materials. YETI, on the other hand, provides a recycling program specifically for its Rambler tumbler — though this service is limited to in-store locations.

And apparently, some of Gen Z has already moved on to Owala bottles, which are made easy to clean and adaptable to users whether they sip or gulp. The bottles also have really unique designs used for a tool of self-expression.

Bottom line — whatever you're drinking needs a steady companion, not a fleeting fling if sustainability is what you're aiming for.