"Market size" is the phrase suppliers love to cite when they want you to stock their new line. They'll pull out a glossy report, point at a growth curve, and say, "This segment is exploding—you need to get in now." What they won't tell you is that the report might be commissioned by the same manufacturer, or that the "segment" includes only premium devices while they're pushing a budget disposable.

When you hear "market size" in a sales pitch, your radar should go up. Ask for the source and the exact definition. If they can't explain how the number was derived, it's probably not worth much. A credible supplier will be happy to walk you through the methodology—an eager one might just hand you a glossy summary.

A good rule of thumb: if a market size claim supports a decision you were already inclined to make, double-check it even harder.