THE SLEEPWEAR EDIT
Plan a practical pajama rotation.
Use your laundry schedule to estimate a starting number of sets. This is a household planning calculation, not a rule about how often everyone must change.
5 sets: four to cover the wash-and-dry interval, plus one spare.
Make the number fit your household.
Count usable sets in the current size first. Laundry timing, changes after spills and drying space can affect the rotation more than the fiber name. Reduce the interval if you can wash sooner; add spares when a missed load would leave you short.
The calculation rounds up (days between washes + drying time) × sets used daily, then adds your chosen spares. It assumes this schedule stays reasonably consistent. It does not predict drying time or tell you to keep wearing a soiled garment.
For children, buy the correct current fit and follow the garment’s labels. A larger rotation is not a reason to size up snug-fit sleepwear for future use.