Does anyone know how long it takes from someone returning a HIT to when the HIT becomes available on mturk?
And what if you're the one to return the HIT? Can you still accept the HIT that you returned when it becomes available?
I think it is instant, and I think some req will log that you accepted the hit and block you from taking it again but I'm not certain on that, I know I've been told I already did this hit when I didn't but I did work for the req on another hit, but that's mainly with survey req. I've returned lots of batch work and have no problem accepting another batch item from a req. It could even be that they req is logging your mturk id when you open their link and next time see you opened a link, even if you didn't submit to mturk and say 'you already took this hit' or the like.
But if you're thinking can I return a hit and accept it again to 'reset' the timer I think it is easier said than done as others will see it and go for it, it won't be 'held' for you.
Depending on your scripts/settings you might also be hiding hits you accepted and returned BUT are still able to accept more of the hits assuming the req hasn't blocked you from doing more.