My current working theory is anything under $1000 I'll shop around for the best price online here or generally overseas.

Over $1000 I'll shop around in Aus or wait for a sale in which case I can get the price generally to a similar point as buying from overseas once you factor in shipping costs and potential GST on the import.

I don't want to have to worry about possible warranty issues and shipping back overseas on high dollar items.

Items under $1k if they fail and the warranty falls apart atleast $1k is a bearable loss, relatively speaking.