I am 50, and judging from my FB, filled with people aged 48-52 or so, it varies a lot. Those with weight, whether they always had it, or have gained, look older than those who have remained or regained slimness. But a lot of those who were active outdoorsy types have ruined their skin compared to those of us who stayed out of the sun. Those who carried on partying into their middle age look the worst, no matter how much money and effort they put into fitness and hair dye (and cosmetics for women) now.
It helps that hair dye, even for men, is commonly acceptable. And the products and artistry has improved. A lot of our ideas about how people should look at different ages comes from the days when it looked fake and wasnt something regular, respectable mums did. If it werent for getting mine done regularly, using foils and 3 shades of color! i would look exactly like my paternal Grandmother did at 50: OLD.
On the other hand, my mom is 72 next week, and has stopped dying her hair. Which is only about 1/4 grey silver. So although I credit hair dye with making most 50 and older folks look younger, some do have a lucky genetic inheritance. I was more than half grey by 30 and underneath my expensive dye job I am white haired. If I didnt dye my hair, my mother and I would look like sisters. Judging by hair color, you would guess me to be the elder. Thanks dad.