If you are talking about merit sources, then it's 30 days. If I award 20 sMerits today, then I get them back in 30 days. If I can't find any decent posts, because it takes too long to weed through all the rubbish, and I don't award any merit, then the replacement is delayed, and the good members lose out. The spam bots and TwitBook spammers don't seem to realise that they are actually slowing down the generation of new sMerits that could be awarded to the decent responsible members here.