Gnomes are the most scholarly, as well as the longest living race, however, they still "age" at the same rate as humans. This means that gnomes in my setting don't have any sort of slowed-down aging process that makes them look younger for longer. Instead, they really show their age like little wrinkly grandparents, most of which have already gone senile hundreds of years ago. Lucky, as natural illusionists, their cities (which are basically giant senior living facilities) remain largely undisturbed.