A price with no date on it is not information

Before building anything here we read the pages that currently rank for the searches we care about: mat versus mat, best mat for hot yoga, best mat for bad knees. Nearly all of them show prices. Almost none say when the price was true.

One of the better-researched roundups we found, from a site with genuine testing behind it, lists prices in a comparison table sourced to "manufacturers" with no date anywhere near them. The article's headline says one year; its publication date says the year before. A reader has no way to know whether the number is current, six months old, or from the first draft.

Why this is not pedantry

Yoga mat prices move. Over the readings we have taken so far, the same listing has varied by enough to change which mat is the cheaper of a pair. A price from an unknown moment cannot tell you which mat is better value, which is the entire reason it was printed.

It also decays invisibly. A wrong spec is wrong loudly — someone notices the thickness is off. A wrong price looks exactly like a right one.

What we do instead

Every price here carries the date it was read, in the same line, in plain text. Prices are re-read once a day. Anything older than three days is not displayed at all, because a stale price is worse than no price: it looks like knowledge.

None of this makes our numbers better than anyone else's at the moment they are read. It makes them checkable, which is a different and more useful property.