By Laura Vanderkam Sent: Monday February 06, 2012

It’s what Donald Rumsfeld called the “known unknowns.” At some point this winter, your kids will be home sick, and your sitter will be snowed in—or sick as well.

That's why every working mother needs a backup plan. Start here.

• Strategize
  Interview a handful of substitute sitters, including one or two within walking distance—and know their schedules. You want responsible people with flexible schedules: retirees, stay-at-home moms of older kids, or college students.


• Network
  In a pinch, Care.com organizes babysitters by location and lets you filter by sitters who are willing to show up for a sick kid. It can even text your favorites to check last-minute availability.


• Budget
  As for cost: it’s a known unknown, so you can budget for it. If your kids are in day care (and hence can’t go if they’re sick), budget for seven days of back up care and hope to pay for five, says Katie Bugbee, managing editor of Care.com. If your nanny is sick, budget for five days of back up care and hope to pay for three.

Never say never. How much work time have you lost by not having back-up care?

Laura Vanderkam is the author of All the Money in the World, forthcoming in March.