Fit the intended pair before the walk
Choose the exact sock size from its maker’s chart, then try both socks in the intended shoes. Check heel placement, toe room, bunching and cuff clearance. A familiar footwear setup still deserves a new check when the sock construction changes.
Choose one relevant material constraint
If wool-free is required, use the explicit material filter. Otherwise compare the full construction rather than treating the largest wool percentage as a benefit by itself. Keep the care method you can use in mind.
Decide whether to carry a spare
A spare is a deliberate contingency, not a universal count. Consider the expected wet conditions, the footwear and your own preference for a dry change. If it is a liner system, count the pieces you mean to replace.
Keep the spare available for its purpose
If the spare is intended as a dry change, treat it separately from the pair in use. A plan that assumes it remains dry still depends on how you carry it. Do not count a reserved pair twice in a longer-trip rotation.
Finish with the care instruction
After the walk, use the exact label and maker guidance. A general wool routine is not automatically appropriate for every synthetic, membrane or layered product. The care lookup gives the available source-backed instructions.
For early rubbing, shifting fabric or a damp change, follow the hot-spot prevention guide before continuing your sock fit experiment.