You've just gotten a new job! That means you'll be earning a bit more — so you go out to celebrate and buy yourself that nice car you've been looking at. Or perhaps you've finally finished paying off your mortgage, so you let yourself eat at restaurants more often, and start getting a nicer coffee on the way to work every day. Then you look at your bank account and wonder where all the money went! Something called "lifestyle creep" might be to blame. Lifestyle creep, also called "lifestyle inflation," is when you find yourself with some more money — for example, after getting a new job or paying off a mortgage — but then spend more as a result. You find a new lifestyle creeping up on you like a monster from behind the sofa! It's easy to do: you feel you've earned the right to enjoy yourself and treat yourself to some small luxuries. But experts warn that this can quickly get in the way of your financial goals — if you're saving for retirement, for example. And if you get used to the changes you've made to your lifestyle, you could even end up in a worse position than you were in before. Of course, we all need to treat ourselves from time to time. But if you find you're not saving any more even as your income has increased, that may be a sign that you need to make a change, according to finance expert Robin Aiken. The trick is to stick to a budget, even as you begin to earn more. You can still enjoy nice things, says financial planner Paco de Leon, but try to avoid too much impulse buying — that's buying something without giving it much thought. With some smart saving, you can make that extra income go a long way — and keep the monster behind the sofa!