Found this photo of Isaac Newton interesting.
Isaac Newton

In this picture he is wearing a wig, common to the late 17th century, as a fashion accessory, to hide baldness, and bad hair days. It was perceived as part of a classy man's wardrobe.
I will include a common picture of him with his natural hair. Some say, that men often shaved their heads and wore wigs, because of lice and other problems of the times.
However, some wore the wigs occasionally, like some would wear a three piece for important meetings with the bigwigs of the company.
From what I know, during this period in France, rich men and even women shaving their heads and wear wigs.
It was for hygiene purpose. They were avoiding water because they were thinking that was the cause of illnesses and didn't wash often. To hide bad smells, they used perfume.
Fortunately, today, we take a shower every day!