Setting powder does more damage to mature faces than any other product, and almost all of it is avoidable. The damage is not caused by powder as a category — it is caused by coarse powder, applied everywhere, swept on with a fluffy brush, over oil that was not blotted off first. Each of those four is a choice.
Milling is the only specification that matters. A finely milled powder is made of very small particles that sit flat and scatter light smoothly. A coarse one is made of larger particles that sit in the low points of the skin — which on a mature face means every fine line, every pore and every crepe line — and light catches on them. That is why a crease can go from soft to defined within seconds of powdering, and why the same powder looks fine on a smooth forehead and dreadful under an eye.
Placement is the second variable. Powder exists to absorb oil and to stop product moving. On a mature face, the places that produce oil are the nose, the center of the chin and a strip of forehead, and the places where product moves are the nose bridge and sometimes the under-eye. Everywhere else, powder is doing nothing except sitting in texture.
Technique is the third. A fluffy brush swept sideways across the face drives powder into every crease it crosses. A small dense brush or a puff pressed down leaves powder on the surface. This is the same press-don't-sweep rule as everywhere else on this site and it matters most here.
And blotting is the fourth. Powder applied on top of oil makes a paste, and paste in a crease is worse than oil in one. Paper first, then powder.
It is also entirely legitimate to use no powder. If you wear a light base and your skin does not shine, there is nothing to set.
