If you're thinking about purchasing your first home, you'll need a lot more cash than you might expect.

Buyers who don't think beyond how much they need for a down payment are in for a lot of nasty surprises.

Owning a house is much more costly than renting. Utility bills are usually higher. All of the improvements you want to make will cost more than you think. Routine maintenance will nickel and dime you to death. And the big emergencies, like a broken furnace or flooded basement, will drain your checkbook in a hurry.

That's why some financial experts suggest that new homeowners need at least 5% of the purchase price set aside for unplanned expenses and home repairs.

Then there's the issue of how you'll pay the mortgage if you lose your job.

One thing the Great Recession taught us is that every homeowner needs to have at least six months worth of mortgage payments in the bank. Nine months is even better.

Far too many families lost their homes because they were living paycheck-to-paycheck and didn't have enough savings to make even one mortgage payment after being laid off.

That's also why it's important to buy a home that doesn't gobble 40% or more of your monthly income.

Spending too much on your mortgage payments can quickly drain what you've saved and leave you wide open for a financial crisis.

If you're thinking of buying a home, first figure out how much you can afford to spend.