Locclo wrote:Thankfully, I'm usually pretty careful about my models. They're more in danger of going years without getting painted than getting lost or destroyed.

This. If we count long-term neglect (unbuilt and/or unpainted for more than, say, two years), then I've wasted the majority of the money I've spent on models, which probably amounts to about half of what I've spent on the hobby, in total. Luckily, that's not
lost money, simply temporarily displaced. I could keep going at my current pace for half a decade, probably, requiring only the occasional resupply of paint. In that sense, at least, I'm glad for my meticulous nature - I have fewer finished models to show for it, but not a single part of a single model has been lost or wasted.
As for what I'd consider
actual waste... Probably about $10 in materials and numerous hours of time spent on very early terrain projects that I don't consider up to snuff. I should really get around to scrapping those, actually, to free up a drawer's worth of space. They're so crude (by my standards, at least) that I don't even count them as a learning experience.