Skin cells form beneath the surface and flake off. Using moisturiser has no long term benefit, scientific fact.
It may make your skin feel less dry, smoother and more comfortable, though, so use it if you want to.
Sun protection has proven benefits so a high factor sun cream or block, reapplied regularly, is your best bet. Don't sit in the sun, stay in the shade or use a parasol.
Foundation with a high SPF is useful too - although it can settle in lines and wrinkles, making you look older!
Retinol can increase collagen production but use with care (perhaps start with a little a little, and overnight) as it can also irritate your skin.
Hyaluronic acid supplements, taken daily, can reduce skin dryness after about a month of regular use.
(Ask a scientist, not a beautician.)