A character angsting about how they're getting old is a great source of drama. But how do we kick off this drama? What are some cultural signs of getting old? A milestone birthday? Nope. How would we iron out the birthday business to get to the development of the character's angst? Besides, we might ruin the appeal of the character's Vague Age. Bodily malfunctions like creaky joints? That might imply too old an age. Gray hair? People of all ages get those. But it's mainly associated with middle age. And it doesn't have any lasting impact, as long as they're removed or dyed over. And if it's only one strand, it's not immediately visible to the naked eye. Besides, it's just hair color and doesn't really impact anything else, other than the angst and freaking out about getting old that it is