When I started working full time at the age of 24, I was told that it seems silly, but you need to start saving for retirement.   So I got a second job and for the first two years, ten percent of my full time job income went into a 401K and about half of my income from my second job went into a IRA.    My friends were all buying new cars and telling me I was insane "wasting my money" but now nearly 30 years later, I'm so glad I sacrificed and did it.