Go to a place where it's sunny all the time. Then go to somewhere where it's cloudy all the time. You'll notice the difference when looking at older people's skins. So hydration and sunscreen are for sure helpful. All the other aging stuff... Dunno, but I think at least some of them are.
Hydration, sleep, proper nutrition, limited sun, and a bit of a cream/oil/barrier for those with naturally dryer skin is important. Stay away from things that cause you inflammation, like smoking, alcohol, and drugs, that cortisol will age you so fast.
Reminds me of when I used an anti-wrinkle cream as a hand cream once. It anti-wrinkled the skin on my knuckles, so making a fist, the knuckle skin went so tight it started to tear.