The short answer on Whistles Navy Bag is below, and the honest version is that it depends on two or three things rather than one. Price splits into materials, labour, volume and brand margin, and only the first two are visible in the product. Small production runs cost more per unit, which is why a lesser-known label can be dearer than a famous one. A strap drop under 22cm will not clear a winter coat. The groups below run from the decision that matters most to the ones you make afterwards.

What decides this is capacity, closure and strap drop. Everything else is preference. Two from the first group show the range: Antler USA's Backpack in Navy - Urban Light at $150, and Freja's Caroline Bag Fig at $268. The first is the easy entry point; the second is where the money goes. Leather darkens where your hand sits, which is not damage; it is the bag settling. Unlined canvas is lighter but shows every mark; treat it before first use. A higher price mostly buys materials and finishing, and occasionally it buys nothing at all.

Match the bag to the day, not the outfit. One structured bag does more work than three soft ones. From the second group, Antler USA's Essential Weekender Bag in Navy ($120) is the one that earns its place, because it works in more than one context without being restyled. The third group is smaller and deliberately narrower, bags, for the decisions you make after the main one. None of this needs the whole group. One piece from each is usually enough.

There are 20 bags here from 12 brands, $26 to $695, all in stock when this was written. We would not buy all of them, and neither should you. Nobody's Child's Navy Embroidered Pouch at $26 is the low-risk way in, and Liffner's Belted Bucket Bag Navy Suede at $695 only makes sense if this is a category you already use constantly. On whistles navy bag specifically: the difference between the top and the bottom of this list is real but smaller than the price gap suggests. Nothing here is included because it is famous, and price is not used as a proxy for quality anywhere on this page. If you take one thing away: if you would not buy it at full price, you do not want it on sale.