U can legally buy ONE knockoff of one thing. One iPad, one camera, one jacket, etc. China sells a lot of stuff with no brand name, or a Chinese brand name, so u can buy as much of that stuff as u want.
I bring winter and beach wear every trip longer than about 4 days...u may end up in ANC or SYD on any trip, and one of them will be cold or hot. Your schedule can change so much that you can have any weather on any longer trip.