The middle classes are basically the wide swath of people between noticeably poor and noticably wealthy. Obviously it is very difficult to define where the boundaries are because it is a combination of wealth, attitude, background and so on. But I know it when I see it.
Probably the best way to describe the differences is by the different “track” people take in life. Class destinctions will tend to keep people on those tracks.
For most people in the middle classes, their track is to go to school, if they are lucky, go to an average college and then get some job they tolerate for the rest of their lives. They drive average cars. Have little to no sophistication or worldliness. Typcial jobs would be teacher, office worker, dental assistant, paralegal, and so on.
I would characterize myself as “upper middle class”. A minor distinction, but generally characterized by going to better schools and working in better jobs. Types of CAREERS would generally be accountant (CPA), doctor, lawyer, finance. Basically highly paid white collar working class.
The separation is probably more noticeable in a public high school. The UMC kids would be the clean cut kids who are involved in lots of activities and go to private university, eventually working in the Big City. The middle class kids go off to state college and don’t really wander far from their home town.
The wealthy kids, you don’t even see because they are off in private school. Or if you are a UMC kid in private school, they are the kids who’s dad owns this and that and the other thing.
And of course there are all different levels of “wealthy”. If you make $200,000 a year or are worth several million in assets, you’re a pretty wealthy guy. But not compared to a multi-billionare.
For New York area, a quick guide is to go by where people “summer”:
Upper Classes - Hamptons - Own their own house
Upper Middle Class - Manasquan, NJ; LBI; Fire Island, NY - Summer share with college or work friends
Middle Class - Belmar, NJ; Avalon, NJ - Week rental with high school friends
Lower Classes - Jones Beach, Wildwood - Day trip with the cooler