We love the fact the kids have left, but we really enjoy them visiting now. I agree with Toky, you get to run around in your undies, leave doors unlocked,and have your lives to yourselves, you don't have to stock up on lots of coke and crisps. I too now have total control of my clothes, bags etc., and my husband has a lot more sock and aftershave than he had before.
However, word of warning, my daughter got her own flat after she finished Uni and was about 25 miles from us. So after a couple of weeks she came up and spent the night. The next morning she told me she loved the new pillows on her old bed. I said to her that I got them locally and would get her one for her flat, don't worry, she said, I have one of yours in my bag already!!!
I also think you should note that kids will return to your home and open the fridge and take out food just as if they still live with you.