BOGOF offers can be a real help for large families, of course- but I think they are too tempting, without the thinking attached. If you do not have a very large family, BOGOFs have to be planned, frozen, cooked and frozen, etc- but it takes time and a bit more planning- which is sadly often missing.
I went to Tesco and bought a bag of tangerines- at the till, the cashier told me' go back and get another bag, it is a bogof offer'. I replied that there are only 2 of us and they will be wasted 'doesn't matter she said- just take them'. I have often got bogof offers and dropped the free bit at a friend's with children. Even worse with meat- where the second chicken often ends up in the bin after a week, instead of cooked into a curry or pot- for a few days later, or frozen. Tragic really.
I do wonder if the waste related to BOGOFs is not acutally part of the marketing and planning!