That is quite amazing. You can't possibly live in NYC, can you? At least not in a place that has a roof. Granted I have a mortgage and a kid but saving 70% with rent, a car, and a need to eat !!!!!!!!! You are either very disciplined or really, really, really like boxed macaroni and cheese.
No - I live right over the river in NJ now, primarily because of tax reasons. Before that, I lived in a rent stabilized apt (about 1000/mo - 650 sq ft) for six years. That took me through business school, through associate, and to VP. Since I graduated business school, I have saved from 50%-70% of my take home per year. Yes, I work in a highly compensated profession, but its not all that hard if you have some discipline. For example, while many of my coworkers were moving to swankier places, I was staying in my rent controlled closet. When many were flying first class to Bora Bora, I was golfing in North Carolina. When many were eating out at $200 a night, I was making my own stir fry. It adds up fast. Then, before you know it, you have a nice chunk of money that is only adding to your income even more.
When making discretionary purchases, I usually employ the "24 hour rule". That means if I still want it in 24 hours, it will probably be a worth while buy. While Im doing that, I always think about all of the things that I have purchased that I now wish I could have the money back on. (If you think about it - there are a lot of them!). Well, since I didnt buy it, I can have the money back right now - if you get my drift. This strategy usually prevents most dumb purchases.