Counting wears is the right method and I got the opposite answer from it, so the count is worth doing yourself rather than borrowing.
My second pair is a flat sandal that weighs almost nothing and packs flat. Worn most evenings, every shower, and as the thing I put on when the walking shoes are drying. It is not a second pair of shoes, it is a different function.
The advice to take one pair is really advice against taking two pairs of the same kind of shoe.