It went down for me, but my daughter got married not long after I retired (I did pay a crazy amount for the wedding, but my expenses have gone down because I'm not supporting her anymore), I made sure I paid down a lot of debt and I dipped into savings to pay off the house. So, my expenses are the basics plus travel, which we do quite a bit of, but airfares have been relatively cheap and we look for deals - we're flexible, now that we're retired.
I'd say the biggest savings we've realized is we're not eating out as much. When we both worked, it was too easy to eat out. Now, we generally eat out a couple night's a week, because we have time to prepare meals at home.
Overall, I'm probably in much better financial shape 9 years after retirement, but mainly because I took care of the debt. For me, that's the key.
In our case, we're getting by on about 60% of pre-retirement income and it allows us to stay out of our IRA or only dip into it for big-ticket items. With the stock market going gangbusters, our IRAs have grown way beyond what was expected. Of course, there's always the chance of a major downturn.