Honestly I don't know, but I think it's every 5 mins. But was how it was in the earlier versions of LW. But now it's quite different. Only if you force a file to resume (from the incomplete folder in the Lib window) will it continually search fot resources every 5 or so mins. As far as busy/cued files go I'm not sure but I think it's much, much more frequent. (There can be a drain on the netwk if everybody's files that're not dwnlding are continually looking for resources - And I mean a 'particularly' slowed down netwk for everybody!) I'll leave the 2nd part of the question to those more in the know.