Here is the number nobody writes on the fridge calendar: what the split week actually costs. It is not only the gas or the sitter. It is the afternoon you spent in the car, the call you took from the pickup line, and the work you finished at 9pm because the day had two houses in it. Some of that cost shows up on a receipt. Most of it you feel. The useful move is to name each part, then ask what makes it bigger or smaller in your own week.

Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.

Start with the minutes, not the miles

Count the drive from your house to your mom's, then from her house to school, then back again. Do it for an ordinary week, not the best one. The distance between the two houses is the biggest single driver, but the minutes change with traffic, the time of day, and which route the bus or the practice pickup forces you onto. A quick hop at 2pm on a clear day feels nothing like the same hop at 3:15 when the line of cars wraps around the lot. Write down the real minutes, because the minutes are what you are paying for.

Count the handoffs

Every time a child moves from one adult to another, or you leave one house to be in the other, there is a cost: a text to confirm, a bag that did not get packed, a gap where nobody is watching the clock. More handoffs usually mean more cost, even when each one looks cheap. Ask which handoffs are planned and which are rescues. Planned ones get cheaper when they happen in the same place at the same time every week. Rescues cost the most, so the question to ask is what creates them.

Price your own lost hours

If you cover a gap by stepping out of a meeting, moving a deadline, or working later, that time has a value even if nobody sends you an invoice. Be specific about which hours are paid, which are flexible, and which ones your job quietly absorbs. Hours that can move to another day cost less than hours that vanish from your week entirely. Compare the two honestly before you decide which afternoon to protect.

Compare paid help against the unpaid gap

When the afternoon has no one in it, the choice is rarely between paying and not paying. It is between paying for an hour of help, paying with your own time, or letting the gap sit with no one ready for it. If you look at paid non-medical help at home for the afternoon window, check what is included: the hours actually booked, how travel and minimum visit lengths are counted, whether a helper can be swapped when someone is sick, and what the first week looks like. Ask what the helper will do, such as company, meal prep, or errands, and get that list in writing. Anything about medicine stays with your family, your mother's doctor, and her pharmacy. Ask for that line to be written down too, so nobody has to guess later.

Look for the costs that repeat

Some expenses hide on the kids' side of the split week. Extra activity rides, a sitter for the hour between school and your return, takeout on the nights you did not get to cook, a forgotten gym bag, a second set of lunch supplies. None of these is large alone. Together they show what the split week really demands. Keep a short list across two or three ordinary weeks, then look for the one or two items that keep coming back. Those repeats are the first place to trim.

What pushes the total down

Shared routines lower the cost. A standing pickup on the same days, one calendar that both houses can see, a bag that lives by the door, and a rule for who calls whom when a plan slips all cut the friction. Shorter trips help, so group errands on the same side of town when you can. Ask the school and the activity coaches which days they can move, since one fixed change can remove a whole round trip. Small rules add up, and they do not require you to be a better daughter or a better mom. They only require that the week holds fewer surprises.

What pushes it up

Last-minute changes, unclear ownership of a task, and a single point of failure, whether that is you or your car, will raise the cost fast. If you are the only driver, the only person who knows the schedule, and the only one who answers the phone, every glitch lands on you. Notice which of those is true in your house. The cheapest fix is often not a new service but a second name on one task, written down, so the call does not always come to you first.

Before you decide

Take one ordinary week and track the minutes, the handoffs, the hours you moved, and the extra purchases. Then ask three questions: which cost repeats, which one you can move to another day or person, and which one the family can agree to carry without you. Write the answers on the same page as the calendar. The split week will still be a split week, but you will know what it costs and where to push. For more on how the two halves of the week fit together, start with The Kids' Week and Mom's Week.