(MONEY Magazine) – MARLENE GONZALEZ doesn't act her age. The 28-year-old bought her first house in Las Vegas 2 1/2 years ago, her second last fall. She rents one and lives in the other with fiancé Tom Robinson, 34. The next asset she wants to build up is her 401(k), now worth just $3,000. So in January, Gonzalez hiked her contribution from 3% to 10% of what she earns handling slot jackpots at a casino. "It sounds like a lot, but I don't feel it," she says. "I know that it will make a huge difference 30 years from now." The natural-born saver does occasionally splurge. She just put in a $37,000 pool, paid for with a home-equity line of credit. Yet she's quick to add, "It's part of my investment." --MICHAEL J. POWE