I've found that the "redouble" call is nearly useless. For high level contracts, I absolutely never redoubles because the risk is too high (usually when I place a high bid, I'm not sure if it can be made, especially when the opposing contract has a high chance to be made; moreover, a double usually indicates awkward distribution). For a low level contract, I've found only 2 uses of redouble in my system: 1. For bids between 1H and 2D, I redouble the double when I feel that it can be made, i.e. redouble to game. 2. I use redouble to replace a raise to partner's bid if it is doubled by the RHO, as to save bidding space. Moreover, I never double a bid between 2H and 3D for penalty unless I can guarantee an immediate set (like holding AKQJT9 when RHO is the declarer of a 2NT contract), because if it is made, they would be doubled to game. When will you redouble opponent's double in your method? I would like to know.