Track linen like money.
Every send, receive, wash, and discard is recorded. Know how much linen you have, and how much is with the laundry — right now.
Send to laundryReady to use → At the laundry
Receive from laundryAt the laundry → Ready to use
New stock addedAdd fresh linen to the book
Thrown away / lostDamaged → Discarded
Nothing is ever overwritten — corrections are always on record.