Most of the time DRL's are useless and wasteful. There are however many situations where their use is helpful, and adds a measure of safety. The trouble is that the vast majority of drivers out there are too ignorant, distracted, incompetant, inconsiderate, etc. to know when to turn their lights on, and when to turn them off. Government enters in, and as is usual in these cases, the competant few are punished by the sins of the masses. I keep mine on all the time because I come under the category of "forgetful".

Koz.