There’s a term in software development called “scope creep” which means additional requirements getting added while the project is underway. Scope creep has the potential to delay your project or even derail it in the worst cases.
A phenomenon in urban design relates to traffic on a highway. When traffic is bad on a highway, what should you do as a city planner? One answer is to build additional lanes on the highway to alleviate traffic. However, what usually happens is more people get cars to drive on said highway, keeping traffic in equilibrium.
How does this apply to your lifestyle? Lifestyle creep is when your budget/lifestyle/costs expand to meet your higher income. You move into a nicer apartment, spend more money on trips, eat at nicer restaurants. There are a million ways you can spend your money, but much fewer ways to earn it. This concept is related to the Hedonic treadmill concept.
When you’re starting out, you likely have a negative or near-zero net worth. At this point, lifestyle creep shouldn’t really be on your mind. It’s important to realize you have human capital that can grow over time through education and experience. Investing in yourself will pay off in the long run. (Debt is ok as long as it’s an investment in your future. Credit card debt usually isn’t such).
Lifestyle creep arrives when you get that first big pay bump. It’s tempting to buy that item you’ve been eyeing for ages. There’s nothing wrong with buying it. It’s only a problem if that becomes your norm. You eventually habituate to having nice things and your ability to save money evaporates. Money gives you optionality whereas lifestyle creep traps you in a more expensive lifestyle for the same amount of happiness.
Adjusting your standards upwards is easy (million ways to spend money). Adjusting your standards downwards can be very painful.