A) Paying for your own healthcare B) Saving for retirement C) Saving for buying a house, a car, retirement, a wedding, future children, or other large purchases? D) Paying off your loans for undergrad?
Because my girlfriend and I are 22, make over $100k, have less than $30k a year in expenses combined, and still feel a little "tight" on the budget. But we're both maxing our 401ks to the company match, paying for our healthcare, and paying down our student loans (over $60k) in 3 years. Plus saving for a house, and maybe even a little wedding and a vacation. $100k goes quick.
Note that we both drive 6 year old cars and have no plan to replace them, rent a relatively small apartment and keep our expenses below $2.5k a month combined which is pretty good. I don't feel poor by any stretch of the imagination, nor am I complaining, and the situation is improving steadily as we pay down debt and have more cash, but the saving really puts a crimp on how much "fun money" I have.
We are currently (again with 2 people) putting over $3k a month into savings and paying down debt which are prudent decision but don't feel all that fun and don't really make us feel any "richer".
Let this be a lesson to other grad students out there: save like heck, 'cause you never know when there's going to be a gap in your funding, or a change in its level.