Depends on where you posted it, but generally the beginner forum gets more traffic that some of the subforums.
You generally keep the same supplemental lifts for a while (I know "a while" is vague), they're lifts to help you work on weaknesses.
Ex. Your bench stalls an inch off the chest, you do supplemental work with a one-board or a two-board.
I think the minimum is a month, max would probably be 3 months, if you haven't improved your weakness by then you need to dig a little deeper and try to figure out what's actually causing the weakness and maybe set a new supp lift to address that.