Age spots — sun-induced areas of concentrated pigment, usually on the cheekbones, temples, forehead and backs of the hands — are the one complexion concern where concealer massively outperforms foundation, and where almost everyone uses the wrong technique.
The reason foundation loses is area. A spot is a few millimeters across and considerably darker than the skin around it. To cover it with foundation you would need foundation at a coverage level high enough for the darkest point, across your whole face — which is a lot of product everywhere to deal with four small marks. A matched concealer placed on the mark alone solves it with a fraction of the material.
The reason the technique matters is pigment density. Covering a dark mark requires a concentrated layer of opposing pigment in exactly that spot. Blending — the instinct everyone has, because blending is what you do with concealer under the eye — spreads that concentration thin across a wider area, so the mark comes back through and you have put product on skin that did not need it. Press, do not blend.
The other common error is shade. Under the eye, a half-step lighter can look brightening. On a spot, a lighter concealer leaves a pale dot — and a pale dot on mature skin is as visible as a dark one, just differently. Match your own tone exactly. If your spots are very dark, the answer is a second thin layer of the matched shade, not a lighter shade.
One more thing worth saying because the alternative is often being sold alongside the cover-up: this page covers marks cosmetically. Reducing them is a skincare and dermatology question, and nothing in a makeup bag does it. If a mark changes shape, color, size or texture, that is a doctor's question, not a concealer question.
