I'm a stock control team member at one of the larger outlets, a normal day for me starts at 5pm with potential reductions (Job 14) I look for items on the days date and reduce those (we can reduce items by 90% after 7pm, remember that night shoppers) and if there's enough on tomorrow's date and stock for tomorrow in the warehouse, they may also be reduced (the rate of which is worked out by a database system, the more stock, the higher the reduction percentage) Job 14 for me has always consisted of sandwiches, flowers, produce, bread and fresh cakes, all of which take four hours to complete (making me wish I worked at an express, which would be p*ss easy, and my general routine would take about 20/30 minutes)
Then on the Sunday we do a stock count, this takes 8 hours for all of us (and there are a lot of us) and accounts for everything on the shelves (including the Delicatessen and bakery) and everything in the warehouse. The pharmacy, opticians, clothing and entertainment units do their checks independently to the rest of the stores staff.
There's a lot of skill in the job but ultimately it pays off (quite literally)
Hope that helps.