With a Powerball or Mega Millions jackpot reaching billion-dollar levels, it’s easy to daydream about how you’d spend your newfound wealth. But the odds of winning a prize that big aren’t as high as you might think. In fact, a few years ago, lottery organizers made the game’s top prizes harder to win by adding more numbers to the drawing. This means the pot keeps rolling over after each draw, driving ticket sales and generating publicity.

Lottery winners can choose whether to receive their winnings in a lump sum or annuity payments spread out over 30 years. This decision could affect their total payout by millions of dollars. If you’re thinking about a big change like this, it’s important to consult an experienced financial planner.

If you don’t, your tax liability could balloon. If you take the lump sum option, you’ll get less money upfront, but it will cost you a lot less in federal taxes. It’s also important to consider how much you’ll have to pay in state and local taxes, which vary by location.

Finally, it’s smart to keep your name out of the press and tell as few people as possible about your winnings. That way, you can avoid being targeted by scammers and long-lost friends who want to cash in on your good fortune. Each state’s law differs, but you can usually request anonymity when you pick up your prize. NerdWallet’s Mega Millions and Powerball lottery experts explain how this works.