[GeneralAntilles]

Supplementing vitamin D is unlikely to hurt in most cases (if you're taking a useful form like D3 and if you're not acutely deficient in vitamin A and K2), but it both isn't that effective on its own—oral supplementation tends to take a long time to fix deficiency and may work particularly poorly for people with absorption issues—and doesn't provide the full benefits of sun exposure (nitric oxide being a big one, but there are other immune, blood pressure, and inflammation benefits, as well as stuff related to how vitamin D is produced through sun exposure to the skin).

For me, better mental, cardiovascular, immune, and bone health is more important than apparent skin aging and a marginally increased risk of skin cancer, but everybody has to make their own trade-off decisions. A moderate amount of sun exposure is beneficial to most people. Avoid burning—especially severe burns with kids, which seem to be a big factor in eventual skin cancer risk—by controlling length of exposure and by wearing clothes to cover your skin if you can't control length of exposure.