What is the best way to verify a tool's 'estimated traffic' numbers are even close?

Every tool's "estimated traffic" is a black box. They're all selling you the same recycled data with a proprietary multiplier slapped on top.

Before you trust any of them with budget decisions:

* Cross-check the same keyword/domain across at least three major platforms (SEMrush, Ahrefs, Similarweb). The variance is usually laughable.
* Compare the tool's "volume" for your own known-brand terms against your actual analytics. Spoiler: it's always wrong.
* Remember these are often based on clickstream data from questionable toolbars and extensions. Garbage in, gospel out.

The real test? See if they publish a detailed methodology. They won't. Because then you'd see the guesswork.