Depends on what pathogens/conditions you are dealing with. Personally, the minute I get out of any show the first thing any new pick ups get is a good dose of mite spray and if I have any doubts then I also apply anti-parasite medications as well as keep temperatures on the warm side for all quarantine specimens in order to stimulate their immune systems and kick out any extra pathogens. Wild caughts automatically receive de-wormer the minute they come out of the box.
In the end, quarantine is about keeping your established collection safe, not necessarily the rest of your pick ups.