Most of Australian has kerbside collection (recycling) and most of us look at the piles to see if there’s a spot of gold to be had!
The laws around salvaging or “saving” items that would otherwise be destined for landfill are decided by your local council.
Some councils may have by-laws in place to prevent the activity. But the advice in the majority of capital cities is that any junk left on the kerb for council collection is fair game.
So, while being careful of dangers from the goods (e.g. electrical faults), for which you are personally liable, scavenge away!