Talking to my DM the other day (who is in many respects a bit bonkers) and she asked about the face cream she bought me for Christmas and I said 'yeah it's great although I've nearly ran out of the day cream and still have half a tube of night cream'. She was puzzled until I explained that because I work a lot of night shifts I wear the day cream during the day before my first shift and then again for when I'm at work, I then put the night cream on when I come home to sleep but on my last night I sometimes stay up so have a shower when I get home and put the day cream on again.
You'd think I had just admitted to slathering my face in horse manure judging by her reaction 
as apparently night cream must always be worn at night because the 'air is different' and other gems. I think she's talking pish.
However now I'm throwing it over to you lot and if i am indeed BU then I will concede defeat to my mother (but probably still do it my way as the night cream is too oily to wear under makeup).