New Driver Card

My current card expires on the 9th and the new one starts on the 10th but I work nights so do I have to do the changeover at midnight (I seem to remember reading that in here somewhere) or do I use the new one start of shift on the 9th and just use it for the entire shift??

Oh and my new card expires in 2020, is the new date for a medical even though I’m 45 a couple of years before that ■■

Cheers