Photo: Morgan G Photography

Nobody enters into a marriage believing it'll end in divorce. Yet some marriages end this way. While there's no surefire way to know which marriages will last and which are headed for divorce, there's one group of people who have observed some trends: divorce lawyers. Here are some factors that might predict the length of a marriage, according to the people who have witnessed them fall apart.

1. The price of your engagement and wedding

Weird but true: According to an Emory University study, people who pay more than $20,000 for an engagement ring are three and a half times more likely to get a divorce than those who spend under $10,000. Former divorce lawyer and Wevorce founder Michelle Crosby has observed this with her own clients. “Those brides that blindly focus more on the ring, the dress, and the party instead of the importance of what it takes to have a healthy partnership are more likely to one day sell that ring to pay for their divorce,” she says. Divorce lawyer James J. Sexton agrees. “There's a joke among divorce lawyers that the expense of the divorce is generally proportionate to the expense of the wedding,” he says.

2. How long you've been together

The movie The Seven Year Itch is based on a real phenomenon: Census Bureau data show that couples are most likely to get divorced around seven years of marriage. At this point, Crosby says, “couples are no longer excited by their relationship, and all those idiosyncrasies that were initially endearing become intolerable over time.” Other studies, however, have suggested there's really more of a four-year itch. Either way, the longer you've been together, the more your partnership has proved itself.

3. Your age difference

It's becoming more common for women to marry younger men, but for whatever reason, these marriages seem less likely to last. One study found that women three or more years older than their husbands are 53 percent more likely to get divorced than those who are just one year older or up to three years younger. Crosby can also confirm this one. “We've found that if a woman is much older than her husband, they are more likely to get divorced,” she says. Sexton has actually seen this work the other way around, though, with older husbands and younger wives. “When people with an age difference marry, they need to think more about what that difference will look like in 10 or 20 years and less about what that difference looks like during courtship,” he says.

4. Whether you've rolled your eyes at each other

One study analyzed couples' conversations and found that when they showed signs of contempt, like eye-rolling, they were more likely to end up divorced. Crosby recommends a “five-to-one ratio” to undo the effects of contempt: “For every negative interaction, you need to compensate with five positive exchanges with your partner.”

5. Your incomes

Several studies have found that money is one of the leading causes of stress and conflict in relationships. Maybe that's why lower-income couples are more likely to divorce. Sexton says having two very different incomes or socioeconomic backgrounds can also put a strain on a marriage. When you watch marriages fall apart, he says, “you see a trend where one party was raised in a household with resources sufficient to enjoy ‘the finer things' and the other was raised with less.”

That's not to say, of course, that you'll get divorced if any of these things apply to you. But it's possible that they'll present challenges that you and your spouse will have to work through, and preparing for them can't hurt.

This article was written by GLAMOUR for Brides.com.