A study by Plastic Promise, Netherlands, finds that reusable hard cups that are washed efficiently are less harmful to the environment than any recyclable soft cup, but only if hard cup losses stay below 25%. The tipping point towards hard cups becoming more beneficial was found to be six reuses.

Plastic Promise also found that the margins of comparative benefit of soft and hard reusable cups are slim with even slight changes in the variables and urge that systemic changes are needed to reliably guarantee benefits of reusables. 

Read the full report HERE.