^^^Both my dipped beams went out simultaneously a few months back. Didn't realise until I had to drive home. Swapped one dipped with a main beam bulb and nothing. Meant I had to drive with fogs on. Passed two cop cars and neither said anything. Got them changed within 24 hours with new bulbs which worked fine.
Having said that, it seems to be all the rage the past two years that I've noticed it. Either dipped and fogs or sidelights and fogs. I once tried fogs and dipped on a country road and other than illuminating the kerbs, it did nothing else. It is completely useless IMO and people should be pulled over for it.
I've yet to encounter any weather where I've needed foglights in the past few years. When I lived in Dorset, there were roads where patches of mist would be dense enough to warrant it. For around five seconds. The last time I remember dense fog requiring fogs was when I was about 8. Rear fogs were just about visible and everyone was crawling at around 10-20 mph on the motorway.