How important are routines?

We've all heard, or at least read in parenting books, how important routines are for kids. I think my kids are more flexible than I am! Wednesday I had to go the opposite way, an extra 40 minutes in the morning and another at night, to take J to a friend's because his daycare was closed. Last night I had to take Day to classes back in Salisbury after getting off work, meaning we didn't get home until 8pm. This morning I have a meeting at 8am. I am completely spent. The kids are all fine, but me, I can't wait to get home tonight.