My column on the changes in December women’s magazines from the 1950s to today ran in USA Today this morning as “Mags show how far women have come.” The answer? Quite a bit! Our housekeeping obsession has disappeared–and that’s a good thing.

In some of the pre-pub press on 168 Hours, I’ve been referred to as an “aspiring time management guru,” which isn’t entirely true. I wrote 168 Hours from the perspective of a journalist, interviewing people who’ve built big careers while maintaining their personal lives. But in the course of writing the book, I learned a lot of best practices, which I’ve now had occasion to try out.

For instance, sometimes in the evenings after Jasper (age 2) goes to bed, Sam (2.5 months) takes a short nap or consents to being put down to gurgle contentedly before winding up for his last wakeful stretch. With my hands suddenly free, I look around the house and inevitably see that my 2-year-old has turned it into a wreck. The temptation is to dash around and pick it up. The place will look better, and I’ll feel like I got something done.

But here’s the thing. I know the house will just get dirty again as soon as he wakes up. And since I know I only have about 20 minutes during these stretches, I have learned to ask a question: What is the most important thing I could be doing right now? What activity could I do that is one of my core competencies?

The answer is usually either to do something for work (nurturing my career), to play with Sam (nurturing my family), talk with my husband (ditto), or to do something like write in my journal or read something relaxing (nurturing myself). And so, slowly, I am learning to choose one of these things, rather than putter away the time or do too much cleaning. Time is precious, and should not be wasted on things that aren’t important to us. Writing 168 Hours has definitely taught me that.

I am quoted in a white paper from Ad Age on marketing to moms. Drawing on the “Core Competency Mom” series that I wrote for The Huffington Post, I talk about the genius of claiming that products that reduce housework time give you more time with your kids. This allows marketers to claim that paper plates make you a good mom!

More seriously, I think that setting these things up as opposition (time with kids vs. housework) is just as accurate a view of the universe as what we usually think of as being in opposition (time with kids vs. work). Looking at time diaries, moms do a lot to protect their time with their children (that is, childcare as a primary activity), even when they are working full time. They simply let other things (mostly housework) go.