- Parkinson's law is the adage that "work expands so as to fill the time available for its completion".
While Parkinson's law is famous for comparing it to time, it really applies to most everything. Income, employee personnel, time, etc. Economists like to call the effect on income and expenses "lifestyle inflation". It applies to all of us in one way or another.
Even I'm guilty of lifestyle inflation to some degree. When I was in college I lived off of $12,000 a year. Now I spend closer to three times that amount. Although my income has gone up by 20 times. It's still an example of lifestyle inflation, it just isn't as severe as most Americans, even when you figure in inflation.
Most Americans only save on average about 5% of their income regardless of how much they make. So if they make $50,000 they'll save about $2,500. If they make $100,000 they'll only save about $5,000. Yes they're saving twice as much, but they're spending an extra $47,500 not counting taxes!
There's no logical reason for this. The only time this should reasonably happen is if you incur an extra $47,500 in job related expenses for the extra $2,500 in savings. Which would be completely fucking stupid to do. Parkinson's law strikes again!
Why don't I still live the $12,000 lifestyle? There are a certain number of unavoidable things. If you want to get laid you're going to have to spend some cash. A girl isn't going to want to eat ramen noodles and have pull out sex for every date because condoms are too expensive. This shit doesn't fly after college. Health insurance will increase, as will the amount that you'll need. If you get married or have kids of course all of this goes out the window.
While I'm not saying that you need to live like a gross ass college student for the rest of your life. I am saying that you need to be aware of lifestyle inflation and keep it to a bare minimum. Get roommates, keep your beater of a car, cut the cable, eat in, ride your bike, etc. The college years were some of the happiest of my life. Why not at least try to emulate the good parts of the lifestyle. You never needed to spend a bunch of money to have fun before!