For us as a family, the shampoo bottles are too small and create too much waste. I think it would be great if, for example, the I am range in the stores offered large tubs for self-filling. You could then buy the shampoo once and refill the empty bottle, as long as standard quantities can be selected for filling. Alternatively, I can take my own bottle or a container that I like from the outset and fill it. I scan the price or take a barcode sticker or slip with the refill price to the checkout. The concept is also conceivable for other products, as is already the case in so-called zero-waste stores.