A saving disposition is of course essential to any drive toward self-suffiency. One re-uses all these disposable objects. Net-bags for oranges make good prawn nets. My garden has a serious crop of cut off milk bottles milk bottles doing mini-greenhouse duty. B has been using them too, to make and store broth for the dogs, made from scraps. Fish, chicken, muttonbird... We really, really need that milk-cow. Too many milk bottles and the stuff is expensive.
The key here is of course NOT to be of too saving a disposition. For example not putting on the light while boiling the kettle to make coffee in the still-dark wee hours of morning, but instead using the dim light of the full moon is a mistake.
Or maybe one just shouldn't store fish-and-muttonbird broth in a milk bottle in the 'fridge door.