Unused accessories/attachments for mixers
I think it's almost certain that my mother bought some small appliances that included accessories of some sort that were either never, or seldom used. In her case, some things were for cooking operations that seldom happened in our kitchen. Two examples:
1. A food processor attachment for whipping cream. We seldom had whipped cream. My mother probably would have reached for the hand mixer and bowl, as always. I suspect her interest in the food processor was for new capabilities, not replacing existing appliances.
2. The flat dough blade on the KitchenAid mixer, which might well never have been used. This KA definitely was bought for new capabilities. The selling point was bread dough. Our existing hand mixer was powerful enough that it was more than adequate for everything else. A stand mixer might make lighter doughs easier, since one doesn't have to stand over the bowl, mixer in hand. But in our case, we didn't have space for the KA to live by an outlet. So the "convenience" of not holding the mixer, was balanced by the pain of clearing a certain stretch of counter, and moving the mixer in and out. It was worth it for bread dough. For a light, quickly mixed cookie dough, it was less worth it.
As for the KA, the wire whip might well have never been used, either, except I discovered that it was the best way of whipping egg whites. (At least the best given the available equipment.)