Lots of guessing and variation of same problem here. Its all down to the connection to the mother board as described by a few others. The jack socket is basically placed on the mother board not welded and sits on little gold legs, couple of mm thick, each having a different function, one maybe the mic, another speaker etc. The problem comes from plugging in this will obviously put slight pressure on these pins and they only need to bend a fraction to loose contact, each time you plug in different pressure will be applied so another pin may move slightly causing a reconnection, eventually connection is lost. We have also spent as fortune on differing controllers and headsets. This is a simple problem that microsoft must be aware of but seem reluctant to change, the headset manufacturers must be a little annoyed as they are getting hundreds of working returns.