Unfortunately there is no solid answer for this. All rock is different. I had 2 orders of rock, a month apart, from Walt Smith. First order made my house smell so bad I thought we would need a hotel for a week. Took weeks to cure. Emptied skimmer almost hourly in the beginning.
Next batch, looked the same, but no smell at all. Hardly skimmed. I added to my tank in a week, and would have added sooner if I didn't have other things to do.
Basically, the rock takes as long as it takes, and you use it when it's ready.
As a rough guidleine, semi cured tells me that it's been with them a while and would likely need a week or less. Or not.
I wouldn't buy used rock from anyone unless I knew how old it was and how it was taken care of. If you buy rock that's been covered in detritus for 5 years in some grungy unmaintained tank, you're buying yourself some issues.
And that 5 year old rock was robably bought used from someone else
If you know the history of the rock, and you're comfy with it's quality, then it might be a good idea.
My last concern is if you're just starting out, and already worrying about how long something takes (1 week vs 10 days) then you might want to pick a different, faster paced hobby. The biggest skill a reefer needs is patience
