When does it work best? - that is area specific. If you are in an area where the buck to doe ratio is very low, then rattling is best when used in the pre and post rut as said before. However, if you are in an area where the buck to doe ratio is close to even, then it can be used throughout the rutting season because there will always be few does per buck in heat at any one time and the competition will be more severe.

Does it work? - absolutely... sometimes It certainly isn't automatic, but it can occasionally bring a buck in.