In practice, get to the cause and the treatment tends to pick itself. That is why the first job at a consultation is working out why your skin feels the way it does. Still, a handful of drivers account for almost all rough texture and enlarged pores.
Ageing is the quiet one. As collagen and elastin production slows, the skin loses the scaffolding that holds it taut. So the surface softens and pores lose their spring. Sun damage speeds all of that up, thickening and coarsening the outer layer while breaking down the collagen underneath. That is why a daily sunscreen matters as much as anything done in clinic. The NHS guidance on sunscreen and sun safety is the plainest summary of why.
Oil and genetics set your baseline pore size. Likewise, oilier skin tends to carry larger, more visible pores that trap dead cells and congestion. Dead skin build-up from skipped exfoliation leaves the surface dull and gritty. Past acne is the other big one, since inflammation can pit the skin and leave textured scarring behind. Lifestyle plays its part too, as smoking, heavy drinking and a poor diet all show on the surface eventually.