I've been trying to understand and reduce my impact on the environment, and particularly to understand what a really sustainable lifestyle would look like. I (roughly) get the concepts of ecological footprint and planetary boundaries.
But one of my difficulties is how to account for the impact of buying secondhand goods. I tend now to buy nearly everything from charity shops, eBay, etc and buy very little new "stuff". A simplistic viewpoint is that these have zero impact (other than shipping and other overheads). But that seems like a bit of a cheat. In particular it fails the test of "would it work if everyone lived like this" since it relies on someone else having bought things new. A bit like countries offshoring all their carbon emissions and claiming to have reduced their footprint.
Any ideas for how to do this in a practical way?