Use the resupply segment as the unit
Enter the days between the wash or replacement opportunities you actually plan to use. A months-long route is not one unchanging drying environment. Repeat the calculation for segments with different conditions and facilities.
Stress the slow-drying case
Run the same segment with a longer user-entered drying time. If the plan then has no wearable walking pair on a day, change the carried count, wash opportunity or wear assumption. The tool does not assert a fiber-based dry time.
Keep reserve and retirement separate
A reserved pair is excluded from walking rotation. Replacing a worn pair is another decision altogether. A warranty may provide a replacement process, but it does not establish when the pair will wear out or whether that process fits your route timing.
Record the model before replacing it
Keep the exact style, size and variant identity with your packing notes. A similar brand name, successor or retailer-exclusive color does not prove identical composition or feel. Compare the current product label rather than assuming the old label still applies.
Recheck what changed
A different shoe, insole, season, sock size or construction changes the fit check. Use the comparison tool for known construction differences and try the full setup. Long use of a predecessor does not certify the fit of a revised model.