This Is the No. 1 Rule My Husband and I Follow When Buying a Home

My husband and I have purchased several houses over the course of the 12-year period that we have been married. Each time we buy a house, there's one very basic rule that we follow. Here's what that rule is, some details on why we've chosen to enforce it, and whether it's a rule that others might want to look into as well.

Our home needs to be affordable on a single salary or we won't buy it

The rule that my husband and I always follow is that our mortgage payment must be affordable on either one of our incomes independently. We will not buy a house that we could not afford if either one of us was forced to stop working or took a big cut to our income.

We have this rule in place for a few key reasons:

• We're both self-employed and we can't count on a steady income. Since neither of us have an employer promising us a paycheck, our income is a little bit more uncertain than most people's. We don't want to commit to a payment we couldn't make if one of us had a bad month at our jobs.
• We want more flexibility. We don't want to both be pressured to make a large amount of money just to be able to afford a mortgage payment. If one of us wants to take time off to spend with our kids or, worse, if something happens and one of us is forced to take time off due to health or family issues, we want the flexibility to be able to do that.
• We want to accomplish other financial goals. By making sure that we're only devoting around 30% of each of our individual incomes to housing costs, we have plenty of money left over as a household to do other things. Since we have lots of important goals, like saving for early retirement, it's essential we don't overcommit.
• We know a mortgage is a long commitment. It's one thing to take on a large loan for a few years -- but the mortgage requires three decades of payments. So there's more chance of something going wrong financially or of a job change becoming necessary during that time.

Keeping our mortgage costs affordable enough that either one of us could make the payments if we had to gives us a lot of peace of mind. We know that the chances of us being unable to make our mortgage payments is slim. Something would have to happen to stop both of our incomes from coming in for that to occur.

Should you follow a similar rule?

This rule works for us because we both make a pretty good living and have been able to afford to borrow from mortgage lenders to buy houses in the areas where we want to live even while following it. We also have a similar level of earnings.

If you have a big salary disparity between you and your spouse, or if you couldn't afford to buy a house at all if you followed this rule, then it probably doesn't make sense to do so. But if you want a lot more peace of mind and plenty of money for other goals, then it may be a good option for you if it's possible.

The most important thing is to keep your total housing costs below 30% of your household income to avoid being house poor. If all your income is going toward your mortgage and other housing costs, you won't be able to meet other goals (such as saving for retirement). If this is a less restrictive rule than forcing yourself to ensure the house is affordable on each spouse's salary, then you're still most likely going to be OK with your purchase.

But if you want to make the most financially conservative choice and you don't mind scaling down the home you can buy to follow this rule, you may just appreciate the extra peace of mind it gives you.