I first read about regular reviews in David Allen's "Getting things Done", I think.

I agree though, a periodic project review is a must.

I also find scheduled "brain dump" check list super helpful. Basically, a bunch of questions amounting to "what am I forgetting", by listing all the generic categories I'm responsible for (like "Am I forgetting to pay a bill", "are there any house maintenance items outstanding"). Allows me to unload anything that I'm unconsciously holding on to in my working memory.