I think the standard really varies. You have to do what you are comfortable with. I used to be open 7:30 - 5:30 but have gradually decreased as families leave and now I do 8-5. There is no way I could stay open until 5:45 now, that just creeps too far into my evening. For interviews, I just tell them my times and they have to either work within them or look elsewhwere. It's amazing how they can end up conforming to those times if they really want to.