Its amazing how things just jump out at you when you read them with a fresh pair of eyes. I am currently editing stuff I wrote about three months ago.
Some of the mistakes and problems seem so obvious at a second glance that I wonder how I missed them in the first place!
I am finding that about three months is a good amount of time to keep your work in the cooler (if you have the luxury of time of course). It gives you time to forget what you wrote and you almost read it from the perspective of one of your readers – especially when you have a memory as bad as mine!