A Tiffany may have been a rich girl's name in 1970, while by 2000 it might have been lower income. Marion or Madison or Leslie used to be a men's name, and now are almost exclusively female names. You also might run into racial stereotypes. I write as a Southwestern writer even though I am now in Nebraska. I have quite a lot of Latino characters, so my characters are equally divided across socio-economic boundaries. But what of someone who decides that all the "servants" in his book are "Pedro," or "Ramon" and all the high powered businessmen are "Chuck," and "Bill?" If they are working in meat packing, or if it is 1950, you could get away with this.
This is actually part of the point, as far as I'm concerned. I want the name to seem common for the situation into which my character was born...to use your examples, if my story was in 1970 and I wanted a rich girl's name, I might choose Tiffany, but maybe not in 2000. If my book was set in 1950, I probably
wouldn't spread all races equally across socio-economic boundaries; servants would be less likely to be named "Chuck" and more likely to be named "Pedro".
But there are also stereotypes associated with certain names, for good or for bad. People have grinned or raised eyebrows when I've mentioned my friend Bambi, but I've never gotten that talking about Elizabeth. A good friend of mine, whose name is MaryJean, goes by Mary professionally and Jean amongst some of her friends, and MaryJean amongst another set of friends. She does this at least partially because she gets different reactions amongst different groups of people based on the name she uses. Is "Jean" more fun than "Mary"? No, because they're the same person. But to a lot of people "Jean"
sounds more fun than "Mary", so if MaryJean is presenting herself as fun and outgoing, she's more likely to go by Jean. To add another wrinkle, Jean also goes by "Harley", a name that's just a little more "wild" than "Jean".
So I think that a little bit of all of this comes into play...the time and socio-economic status of the character's birth, the location of the character's birth (names in France are different than in Texas), AND, as a quick characterization, the stereotypes associated with the character's given name.