Sunshine and tanning beds
The sun may give your skin a healthy glow, but it also causes long-term damage to the skin. If you insist on bathing wear a hat, especially between 11am and 2pm and make sure you wear high factor sunscreen, even on cloudy days. You should also wear a good pair of sunglasses to avoid wrinkles around the eyes.
The science: The sun's visible light rays, known as ultraviolet A (UVA) and ultraviolet B (UVB) actively break down the skin's fibrous proteins, collagen and elastin. Insufficient levels of these compounds lead to premature aging of the skin. It is the UVA rays that are most damaging to the skin's actual appearance; UVB is linked to skin cancer. Whilst tanning beds do not produce UVB rays, they are by no means a safe alternative to sunbathing.
People who smoke are much more prone to wrinkles, especially around their lips; but even non smokers are at risk of premature aging if they spend a lot of time in smoky places, like restaurants and bars.
The science: smoking deprives the body of oxygen which is needed to keep the skin healthy-looking. If you do smoke and quitting is not a possibility, try to cut down a little and make sure you drink lots of water to hydrate your skin.
Alcohol is another big cause of dehydration and will contribute to the skin's aging process.
The science: drinking alcohol prohibits your body's ability to absorb the vitamins it needs to keep your skin healthy. It also causes the blood vessels to enlarge which, if you drink to excess on a regular basis, can lead to spider veins.