NEW YORK ( MainStreet) — One thing that your kids are unlikely to learn in high school? Personal finance. However, this is likely the most important skill for them to learn. High school is a liminal time when your children begin transitioning into young adulthood. What do your kids need to know about personal finance, and how do you teach it to them? We spoke to some professionals in the field to get their take on what your kids need to know about personal finance before graduation.

What You Need to Know About How to Teach

Ellie Kay, a family financial expert and author of 14 books on personal finance, has raised seven children, making her a practiced hand at teaching personal finance to kids. "Consistency is key," she says, regardless of what age child you're teaching. To this end, Kay recommends that you lead by example. She also states that you need to take a child's personality into account. "Some people are born spenders, and some are born savers," she says. "Teach to them individually and not as cookie cutters."

Remember What They Already Know

Kay states that by the time your kids are in high school they should have a rudimentary grasp of budgeting. "They should learn that the beauty of spending less than you have is that you get to keep what you don't spend," she said. You can teach this through the time-tested allowance, or by giving them a budget for a family trip, letting them keep the balance left over.

W. Henry Walker, CEO of Farmers and Merchants Bank of Long Beach has four kids of his own. He agrees with Kay that an allowance is a great way to start teaching kids about budgeting and personal finance. "It's not just about the allowance," he says, "it's a recognition of different levels of responsibility."

Banking for Beginners

It's a good idea to start kids on saving early on, says Kay, who states that by the time they reach high school they should have enough saved up to put aside $300 to $500 for a mutual fund. "It's a great way to learn about saving, but also the miracle of compound interest." By the time they're 16 or 17, Kay believes that they should have a debit card and a checking account -- one that they can balance to the penny. An additional benefit? In the age of online banking, it's easier than ever to keep track of what your kids are spending money on.

Walker agrees. "They need to know how to write a check and balance a checkbook," he says. It sounds elementary, but in the world of debit cards and online banking, it's not as obvious as it seems. "My 18-year-old called me the other day to ask how to fill out a check." He also adds that teaching kids how to use online banking and financial apps is essential. "Most kids today have access to a computer or a smartphone," he says.