It’s back to school season, and that means it’s also back to guilt for many parents. Guilt that we’re not showing up at enough stuff for our kids, that we can’t hand-decorate their birthday cupcakes, that we aren’t doing enough to help them in classes, or for our littlest ones, that we’re putting them in daycare or preschool at all, that we’re not pumping enough, or that we’re giving them pre-made baby food instead of making it ourselves.

In my book, Having It All, I document how structural forces have conspired to squeeze women’s time from all directions—because we’re spending more time at work while men’s time doing housework has remained stubbornly fixed (at 1970s levels!!), and meanwhile parenting time has exploded with our modern understanding of child development. Amid that impossible constellation of constraints, I urge women to radically prioritize what contributes to their happiness and wellbeing, which means saying no to a lot of other things! It’s like Marie Kondo, but for your time!

So this fall, let’s agree to say no to the uses of our time that drain our spark more than they spark joy. Consider this your permission to say no to all the below, in service of making it all add up, and getting a little more sleep instead.

The evidence on breastfeeding is actually not as good as you think it is. There are credible studies on preventing early-life gastrointestinal illnesses, but not much data to support the wilder claims like raising IQ points. The benefits seem to be front-loaded toward the first few months, and many people think some of them come from the additional contact time “licking and grooming our pups.” That’s where I start to doubt whether we need to make ourselves insane to ensure our little ones drink exclusively breastmilk, even when the delivery mechanism is a bottle. Breastfeeding can be nice—it produces oxytocin, babies are cute, and we want to hold them anyway. I have yet to meet anyone who likes pumping. Finding space to do it, the parts to wash, feeling like a cow, and still needing someone else to give them a bottle? Look, if pumping is working for you, that’s awesome, and I’m so glad! But if it’s not working, whether for exclusively pumping moms or those returning to work, know that both the science and me are on your side if you decide to stop, and do something else with your breaks between meetings instead.

Look, we all want to be good citizens of the world around us, and I’m not here to talk you out of that! But also, I tend to see moms running themselves ragged to do the committee work or the class parenting, in a way that I rarely see dads doing. Some questions to ask yourself—do I want to do this, or am I just afraid to disappoint someone? Did I already take on a similar task, and might it be someone else’s turn? And, is this the right season of life for me to give so much of myself to others, or do I need to conserve some resources, and give back more when things are at an easier stage?

Eating delicious, nourishing food can be a cornerstone of a good life. And sometimes we want to do things for our kids that just aren’t sustainable with this week’s priorities, deadlines, and time crunches. I have literally never heard of a dad making homemade baby food for little ones. Again, if this brings you pleasure then have at it! But if you are feeling harried trying to cut out shapes for faces on your kids sandwiches or hand-roll ravioli, consider that you may be being influenced by people who are misrepresenting reality: The women convincing you that all this is possible with a career are lying, because doing this is their career! If this were your whole job, you might be that good at it too! But it’s not, so consider whether your kid needs fancy food more, or for you to be relaxed, present, and a little more patient because you put on your own oxygen mask first.

Have you ever been doing a job that’s not event management, and been asked to check on the catering, or make a restaurant reservation, because “you’re so good at it”? Economist Lise Vesterlund calls this type of “office housework” non-promotable tasks, because while they tend to make people happy with us, they never show up on a performance review or in a portfolio of accomplishments. A good barometer is whether there are any men doing that thing—taking notes in the meeting, planning the office retreat, mentoring the new associate, or, yes, seeing about the catering. I want to live in a world where we can all share this crucial work of making our workplaces more friendly and fun. But, until then, I think we need to pass on letting higher ups pass these tasks on to us without compensation. Ask how it’s going to show up in your annual review, and if not, ask if it isn’t Sam or Bob’s turn.

The structural economic changes of the last 50 years have left working moms trying to be a Frankenstein of a “Lean In” girl boss at work and a trad wife at home. We’re twisting ourselves into pretzels and yet we cannot create more hours in the day. The reality is that with the load we’re carrying at home, our careers might not be equal to our male colleagues with stay-at-home wives. And with a full-time job, we might not get to chaperone the school field trip as often and need to stop beating ourselves up. In my book I provide a unique economics-y take on that adage that comparison is the thief of joy: Do not compare yourself to someone who doesn’t have the same utility function as you do. Your utility function is the summation of your life’s purpose, based on your dearest held values. It is the sum of all the joy, happiness, and fulfillment you accumulate over a lifetime. And, importantly, it’s unique to you. If someone else is getting ahead at work and you feel behind, it might be because their utility function is more singularly focused, rather than you not being good enough. And similarly, so for someone’s beautiful garden, sparkling possessions, or, yes, intricately decorated birthday cupcakes. Only you know what goal you’re pursuing, and what constraints you’re facing to do that. So stop comparing and start maximizing!

Looking for more evidence-based insights on time, parenting, and what it really means to “have it all”?Dive deeper in Dr. Corinne Low’s new book, Having It All: What Data Tells Us About Women’s Lives and Getting the Most Out of Yours.